1
|
Vasdal G, Newberry RC, Estevez I, Kittelsen K, Marchewka J. The Aviary Transect - A practical welfare assessment tool to improve the management of cage-free laying hens. Poult Sci 2023; 102:102659. [PMID: 37030260 PMCID: PMC10105483 DOI: 10.1016/j.psj.2023.102659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
The Aviary Transect (AT) is a method for assessing welfare in cage-free laying hen flocks, and comprises standardized walks along each aisle screening the flock for selected welfare indicators: feather loss (FL) on head, back, breast, and tail, wounds on head, back, tail, and feet, dirty plumage, enlarged crop, sickness, and birds found dead. The method is quick (20 min for a flock of 7,500 hens), has good interobserver agreement and shows positive correlations with individual bird sampling methods. However, it is less clear whether AT can be used to detect differences in flock health and welfare related to housing and management. The aim of this study was to evaluate how AT findings varied in relation to 23 selected housing, management, environmental, and production factors. The study was conducted on 33 commercial nonbeak-trimmed, white-feathered layer flocks of similar age (70-76 wk) kept in multitiered aviaries in Norway. The most prevalent findings across flocks were feather loss on the back (mean 0.97% of flock) and breast (0.94%) followed by feather loss on the head (0.45%) and tail (0.36%) with differences in feather pecking damage according to the hybrid used (P < 0.05). Better litter quality was associated with a lower prevalence of feather loss on the head and breast (P < 0.05), and addition of fresh litter during the production cycle resulted in fewer birds with feather loss on the head (P < 0.05) and tail (P < 0.001). Lower dust levels were linked to a lower prevalence of feather loss on the head, back, and breast (P < 0.05), and when access to the floor area underneath the aviary was provided at an earlier stage of production, fewer birds had wounds (P < 0.001), but more birds were observed with an enlarged crop (P < 0.05) and found dead (P < 0.05). In conclusion, findings from AT showed that results of the assessment varied according to housing conditions. These results support the validity of AT as a relevant welfare assessment tool for evaluating cage-free management practices.
Collapse
|
2
|
van Veen LA, van den Oever ACM, Kemp B, van den Brand H. Perception of laying hen farmers, poultry veterinarians, and poultry experts regarding sensor-based continuous monitoring of laying hen health and welfare. Poult Sci 2023; 102:102581. [PMID: 36924592 PMCID: PMC10027566 DOI: 10.1016/j.psj.2023.102581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/15/2023] Open
Abstract
Daily farm management practices play an essential role in determining and steering health, welfare and productivity of laying hen flocks. Optimal management requires expertise of farmers and coworkers, especially when hens are kept in complex, large-scale aviary systems. Relatively little sensor-based support is available to farmers, even though numerous research groups are working on developing technologies to continuously detect deviations in layer health and welfare. A survey with laying hen farmers, poultry veterinarians and poultry experts from Western Europe and Canada was conducted to identify and prioritize indicators of optimal and suboptimal laying hen health and welfare in commercial farms. The status-quo of sensor technology and the advantages, wishes, and concerns regarding sensors were additionally assessed to contribute to the future development of a predictive monitoring tool that continuously monitors laying hen health and welfare. A total of 45 stakeholders were interviewed, of which 41 filled in an online questionnaire. Although the prioritization of indicators differed between stakeholders, the majority identified the use of feed and water intake, egg production and quality, sound, activity, and movement of hens as important indicators to assess health and welfare. Currently collected (sensor) data were not used to their full potential, and stakeholders missed the integration and storage of data into one monitoring system with easy visualization tools. Most interest was observed in the use of cameras and microphones to detect deviations in health and welfare at an early stage, to reduce subjectivity of the assessment and to gain more knowledge on layer behavior. It can be concluded that these results could steer research efforts towards the development of continuous monitoring techniques, and enhance their adaptability and acceptability by stakeholders.
Collapse
Affiliation(s)
- Lara A van Veen
- Vencomatic Group, 5520 AD Eersel, the Netherlands; Adaptation Physiology Group, Wageningen University & Research, 6700 AH Wageningen, the Netherlands.
| | | | - Bas Kemp
- Adaptation Physiology Group, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
| | - Henry van den Brand
- Adaptation Physiology Group, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
| |
Collapse
|
3
|
Feather Pecking in Non-Beak-Trimmed and Beak-Trimmed Laying Hens on Commercial Farms with Aviaries. Animals (Basel) 2021; 11:ani11113085. [PMID: 34827817 PMCID: PMC8614341 DOI: 10.3390/ani11113085] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 11/29/2022] Open
Abstract
Simple Summary Severe feather pecking (SFP) is a major animal welfare problem in layers. It results in pain and injuries in the affected animal. SFP is a behavioral disorder and should not be confused with aggressive pecking. The aim of our study was to observe the pecking behavior of layers on farms with flock sizes common in practice and to identify possible influencing factors. We found that SFP occurred in all flocks, but the pecking rate varied widely between flocks. A low stocking density and the provision of a winter garden or free range (or both) had a positive effect and reduced SFP. Keeping mixed flocks of brown and white layers was a risk factor for SFP. SFP occurred mainly in the litter area and only rarely on perches. This finding emphasizes the importance of providing enough litter, litter areas and environmental enrichment. Aggressive pecking and SFP were correlated, which may indicate a higher stress level in the flock. Beak trimming reduced pecking rates but did not entirely prevent SFP. Instead of subjecting chicks to this potentially painful procedure, reasons for SFP should be addressed. SFP remains a multifactorial problem, but in recent years, many risk factors have been identified and included in best-practice recommendations, allowing the housing of non-beak-trimmed layers. Abstract Severe feather pecking (SFP) is a major animal welfare problem in layers. It results in pain and injuries in the affected animal. It was the aim of this study to gain insight into the actual pecking behavior of laying hens kept on commercial farms with flock sizes common in practice. We observed aggressive pecking and SFP in non-beak-trimmed and beak-trimmed flocks of laying hens and investigated possible influencing factors. The study took place on eight conventional farms in Germany with aviaries, including three farms with a free range and a winter garden, one with a free range and one with a winter garden. Pecking behavior was observed during three observational periods (OPs): OP 1, at the peak of the laying period between the 28th and 33rd week of life; OP 2, in the middle of the laying period between the 42nd and 48th week of life; and OP 3, at the end of the laying period between the 63rd and 68th week of life in one laying period. Videos were analyzed using behavior sampling and continuous recording. We found that SFP occurred in all flocks, but the pecking rate differed significantly between the flocks. SFP correlated positively with the number of hens per square meter of usable area, with statistical significance in the litter area (r = 0.564; p = 0.045). The multivariate analysis revealed that access to a winter garden or free range significantly reduced the SFP rate on perches (p = 0.001). The stocking density (number of birds per usable square meter) had a significant influence on the SPF rate in the nest-box area (p = 0.001). The hybrid line had a significant effect on the SFP rate on perches and in the nest-box area (p = 0.001 each). Lohmann Brown hens in mixed flocks had a higher SFP rate (significant in OP 2) than those in homogeneous flocks, indicating that mixed flocks may be a risk factor for SFP. Lohmann Brown hens pecked significantly less than Dekalb White hens in the litter area (p = 0.010) and in the nest-box area (p = 0.025) and less than Lohmann Selected Leghorn hens in the litter area (p = 0.010). Lohmann Brown and Lohmann Selected Leghorn hens showed increasing SFP rates during the laying period. All hybrid lines had significantly higher SFP rates in the litter area, followed by the nest-box area and perches. These findings emphasize the importance of providing enough litter, litter areas and environmental enrichment. We found a significant positive correlation between aggressive pecking and SFP—in OP 1: rho (Spearman) = 0.580, p < 0.001; OP 2: rho = 0.486, p = 0.002; and OP 3: rho = 0.482, p = 0.002 (n = 39) —indicating that SFP may lead to a higher stress level in the flock. Beak trimming reduced pecking rates but did not entirely prevent SFP. Instead of subjecting chicks to this potentially painful procedure, reasons for SFP should be addressed. In conclusion, our data suggest a positive influence of a lower stocking density and the provision of a winter garden or free range for additional space. The hybrid line had a significant influence on the feather-pecking rate on perches and the nest-box area. Aggressive pecking and severe feather pecking correlated positively. We assume that vigorous and painful AP were an additional stress factor, especially in non-beak-trimmed flocks, leading to more SFP in due course. Beak trimming had a reducing effect on SFP. However, our results showed that non-beak-trimmed flocks could be kept without major outbreaks of SFP.
Collapse
|
4
|
Edwards LE, Hemsworth PH. The impact of management, husbandry and stockperson decisions on the welfare of laying hens in Australia. ANIMAL PRODUCTION SCIENCE 2021. [DOI: 10.1071/an19664] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The present review examines the impact of management and husbandry decisions on the welfare of laying hens in Australia. The literature on many of these aspects is lacking for the Australian egg industry, and, indeed, for the egg industry in general. Management decisions that can affect hen welfare relate to the initial farm design, husbandry routines, and staff selection and training. As modern laying houses represent a considerable financial investment, the decisions made during the design phase are likely to affect both the hens and stockpeople for substantial periods. Hens in cage systems may benefit from fewer tiers and greater space allowances. In non-cage systems, the brown genotypes used in the Australian egg industry may benefit from lower structures that accommodate their heavier and less agile bodies. Keel fractures can be reduced by improving the skeletal health and spatial cognition of laying hens during the rearing period, in addition to minimising the distances they need to jump when navigating aviary structures. The addition of a wintergarden to fixed free-range systems appears to be beneficial. Housing hens in mobile units on free-range farms may challenge their welfare, particularly in relation to heat stress. There is also room for improvement in biosecurity practices and health monitoring of hens, as these appear to be lacking at some farms. The current strains of hen used in free-range systems may not be best suited to these conditions, on the basis of their body condition and flock uniformity. Feed quality may also need to be monitored for quality assurance and optimal hen nutrition. Hen welfare during depopulation can be improved through staff training and by reducing staff fatigue. Euthanising spent hens on farm offers welfare benefits over transporting spent hens to an abattoir. Both hen welfare and working conditions for stock people should be considered when designing laying houses to provide suitable conditions for both hens and stockpeople. This will help improve the job satisfaction of stockpeople, which may translate into better care for the hens and may aid in retaining quality staff. Stockpeople must be recognised as vital contributors to hen welfare in the egg industry, and it is important for the egg industry to continue to attract, train and retain skilled stockpeople to ensure that they enjoy their job and are motivated to apply best-practice care for their flocks. Promoting the animal-care aspect of stockmanship in combination with a supportive managerial environment with optimal working conditions may increase the attractiveness of the egg industry as a place to work.
Collapse
|
5
|
Li JY, Liu W, Ma RY, Li Y, Liu Y, Qi RR, Zhan K. Effects of cage size on growth performance, blood biochemistry, and antibody response in layer breeder males during rearing stage. Poult Sci 2019; 98:3571-3577. [PMID: 30895313 DOI: 10.3382/ps/pez102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 02/25/2019] [Indexed: 01/12/2023] Open
Abstract
This study was conducted to investigate the effects of cage size on growth performance, blood biochemistry, and antibody response in layer breeder males during rearing stage. 575 one-day-old Jinghong layer breeder males were randomly allocated into 3 treatments and reared in 3 cage sizes: large (160 × 160 × 62 cm; LC), medium (120 × 120 × 62 cm; MC), and small (80 × 70 × 62 cm; SC). The stocking density of birds in 3 treatments was kept identical and adjusted every 2 wk, from 45 birds/m2 during the period of 0 to 2 wk of age to 12 birds/m2 during the period of 17 to 18 wk of age. Body weight and shank length were measured every 2 wk, and then the daily weight gain and daily feed intake were calculated. Tibia length and breaking strength were determined at 8 wk of age. Blood parameters including malodiadehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), alkaline phosphatase (ALP) and corticosterone (CORT), and antibody titers against avian influenza viruses H5N1 (Re-5 strain) and H9N2 (Re-2 strain) and Newcastle disease virus in response to vaccination were determined at 18 wk of age, respectively. Body weight, shank length, and daily weight gain of birds in LC were similar with those in MC, and were greater than those in SC at 18 wk of age (P < 0.05), respectively. No significant difference was found in average daily feed intake among the 3 treatments from 11 to 18 wk of age. Birds in LC and MC had the similar tibia length; however, birds in SC were smaller (P < 0.05). Tibia breaking strength of birds in LC was higher than those in SC (P < 0.05), respectively. Birds in LC showed lower plasma MDA, GSH-Px, SOD, and CORT contents than those in MC and SC (P < 0.05); however, birds in LC exhibited higher levels of serum antibody titers against H5N1 and H9N2 avian influenza viruses as compared with MC and SC (P < 0.05). Consequently, LC and MC were superior to SC and were beneficial for birds' growth and development.
Collapse
Affiliation(s)
- J Y Li
- Institute of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Science, Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Hefei 230031, China
| | - W Liu
- Institute of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Science, Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Hefei 230031, China
| | - R Y Ma
- Institute of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Science, Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Hefei 230031, China
| | - Y Li
- Institute of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Science, Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Hefei 230031, China
| | - Y Liu
- Institute of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Science, Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Hefei 230031, China
| | - R R Qi
- Institute of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Science, Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Hefei 230031, China
| | - K Zhan
- Institute of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Science, Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Hefei 230031, China
| |
Collapse
|
6
|
Oliveira JL, Xin H, Chai L, Millman ST. Effects of litter floor access and inclusion of experienced hens in aviary housing on floor eggs, litter condition, air quality, and hen welfare. Poult Sci 2019; 98:1664-1677. [PMID: 30535034 PMCID: PMC6414038 DOI: 10.3382/ps/pey525] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 12/03/2018] [Indexed: 11/26/2022] Open
Abstract
With different cage-free (CF) housing styles and management schemes, retailers have developed their own CF criteria. One highly debated aspect is if hens may be kept inside the system for part of the day—during the first few hours after lights-on. Research is lacking regarding the impacts of such a practice on hen welfare, incidence of eggs laid on the litter floor, litter condition, and air quality. This 14-mo field study was conducted to help assess such impacts. Hens (Dekalb White) in an aviary house (50,000-hen nominal capacity) were allowed to have full litter access (FLA) vs. part-time litter access (PLA) from 10:50 am to 9:00 pm, coupled with the absence or presence of experienced hens (1.5% of the population), hence a 2 × 2 factorial arrangement. The measured variables included a) incidence of floor eggs, b) percentage of birds remaining on litter floor at night, c) mortality, d) body weight (BW) and BW uniformity, e) litter condition (depth, moisture content, texture, amount removed, and bacteria concentration), f) environmental conditions, and g) welfare conditions (10 variables). Compared to FLA, PLA had a significantly lower incidence of floor eggs (1.4 ± 0.1 vs. 12.6 ± 1.1 eggs per hen housed as of 76 weeks of age (WOA), i.e., approximately 89% reduction), less manure deposition on the floor (0.53 ± 0.02 vs. 1.05 ± 0.04 kg/100 hens/d, dry basis, i.e., approximately 50% reduction), and lower ammonia concentrations due to drier litter (averaging 22% lower). Inclusion of 1.5% experienced hens in the young flock did not show benefit of reducing the incidence of floor eggs (P = 0.48). The percentage of hens remaining on the floor at night was low (< 0.01%) in all cases from 24 WOA onward. No differences were detected between FLA and PLA in hen welfare conditions, mortality, BW, BW uniformity, bacteria concentration in the litter, air temperature, or relative humidity.
Collapse
Affiliation(s)
- Jofran L Oliveira
- Department of Agricultural and Biosystems Engineering, Iowa State University, Ames 50011-3270, IA, USA
| | - Hongwei Xin
- Department of Agricultural and Biosystems Engineering, Iowa State University, Ames 50011-3270, IA, USA.,Egg Industry Center, Ames 50011, IA, USA
| | - Lilong Chai
- Department of Poultry Science, University of Georgia, Athens 30602, GA, USA
| | - Suzanne T Millman
- Department of Veterinary Diagnostic & Production Animal Medicine, Iowa State University, Ames 5011-1134, IA, USA
| |
Collapse
|
7
|
van Staaveren N, Decina C, Baes CF, Widowski TM, Berke O, Harlander-Matauschek A. A Description of Laying Hen Husbandry and Management Practices in Canada. Animals (Basel) 2018; 8:ani8070114. [PMID: 29997334 PMCID: PMC6071255 DOI: 10.3390/ani8070114] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 11/27/2022] Open
Abstract
Simple Summary Furnished cage and non-cage (single-tier or multi-tier) housing systems are increasingly used worldwide in efforts to improve laying hen welfare. Canadian laying hen farms are undergoing a similar transition, however, little is known about the housing and management of laying hens in these housing systems in Canada. Data collected through farmer questionnaires from 65 laying hen flocks across Canada revealed commonly used management practices in furnished cage (26), single-tier (17) and multi-tier systems (22). Non-cage systems should allow hens to perform natural behavior (e.g., foraging/dustbathing). However, a proportion of non-cage systems either did not provide litter or considered manure as a litter substrate, which could have implications for consumer perspectives on these systems. Daily flock inspections and vaccination schemes were the main practices used to maintain flock health, whereas veterinarian involvement on-farm and in the development and implementation of a flock health plan was less common. Further research is needed to make clear recommendations and to investigate how to facilitate management changes by farmers currently transitioning to furnished cage and non-cage housing systems. Abstract Canadian laying hen farms are transitioning from conventional cage housing to furnished cage and non-cage housing systems to improve laying hen welfare. However, little is known about the current housing and management systems in Canada. This study addresses this knowledge gap by describing different housing and management practices used on farms where laying hens were housed in furnished cages or non-cage housing systems. A questionnaire covering farm and housing conditions, litter management, nutrition and feeding, environmental control, flock characteristics, rearing and placement, health, egg production and performance were distributed through provincial egg boards to 122 producers across Canada. Data were collected from 65 laying hen flocks (52.5% response rate) in 26 furnished cage, 17 single-tier and 22 multi-tier systems. Flocks were on average 45.1 ± 14.59 weeks old (range: 19–69 weeks). Frequencies of different management practices were calculated according to housing system. Most flocks were reared in the same housing system as they were housed in during lay, with the exception of furnished cage layers which were reared in conventional cage systems. Results indicated that a large proportion of non-cage systems were either fully slatted or had manure as a litter substrate, which could have implications for consumer perspectives on these systems. Further research is needed to develop clear recommendations on proper litter management for farmers. In general, flock health was managed through daily inspections and vaccination schemes, whereas veterinarian involvement on-farm was less common. Vaccination, hygiene, and effective biosecurity should be maintained to ensure good health in laying hens in furnished cage and non-cage systems during the transition to these systems.
Collapse
Affiliation(s)
- Nienke van Staaveren
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Caitlin Decina
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Christine F Baes
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Tina M Widowski
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Olaf Berke
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | | |
Collapse
|
8
|
Kaesberg AKU, Louton H, Erhard M, Schmidt P, Zepp M, Helmer F, Schwarzer A. Development of a prognostic tool for the occurrence of feather pecking and cannibalism in laying hens. Poult Sci 2018; 97:820-833. [PMID: 29294110 DOI: 10.3382/ps/pex369] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 11/13/2017] [Indexed: 11/20/2022] Open
Abstract
In July 2015, a German voluntary decree stipulated that the keeping of beak-trimmed laying hens after the 1st of January 2017 will no longer be permitted. Simultaneously, the present project was initiated to validate a newly developed prognostic tool for laying hen farmers to forecast, at the beginning of a laying period, the probability of future problems with feather pecking and cannibalism in their flock. For this purpose, we used a computer-based prognostic tool in form of a questionnaire that was easy and quick to complete and facilitated comparisons of different flocks. It contained various possible risk factors that were classified into 3 score categories (1 = "no need for action," 2 = "intermediate need for action," 3 = "instant need for action"). For the validation of this tool, 43 flocks of 41 farms were examined twice, at the beginning of the laying period (around the 20th wk of life) and around the 67th wk of life. At both visits, the designated investigators filled out the questionnaire and assessed the plumage condition and the skin lesions (as indicators of occurrence of feather pecking and cannibalism) of 50 laying hens of each flock. The average prognostic score of the first visit was compared with the existence of feather pecking and cannibalism in each flock at the end of the laying period. The results showed that the prognostic score was negatively correlated with the plumage score (r = -0.32; 95% confidence interval [CI]: [-0.56; -0.02]) and positively correlated with the skin lesion score (r = 0.38; 95% CI: [0.09; 0.61]). These relationships demonstrate that a better prognostic score was associated with a better plumage and skin lesion score. After performing a principal component analysis on the single scores, we found that only 6 components are sufficient to obtain highly sensitive and specific prognostic results. Thus, the data of this analysis should be used for creating applicable software for use on laying hen farms.
Collapse
Affiliation(s)
- A-K U Kaesberg
- Chair of Animal Welfare, Animal Behavior, Animal Hygiene and Animal Husbandry, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinaerstr. 13/R, D-80539 Munich, Germany
| | - H Louton
- Chair of Animal Welfare, Animal Behavior, Animal Hygiene and Animal Husbandry, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinaerstr. 13/R, D-80539 Munich, Germany
| | - M Erhard
- Chair of Animal Welfare, Animal Behavior, Animal Hygiene and Animal Husbandry, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinaerstr. 13/R, D-80539 Munich, Germany
| | - P Schmidt
- Paul Schmidt, Statistical Consulting for Science and Research, www.statistische-modellierung.de, Zimmerstr. 10, D-76327 Pfinztal, Germany
| | - M Zepp
- Chair of Animal Welfare, Animal Behavior, Animal Hygiene and Animal Husbandry, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinaerstr. 13/R, D-80539 Munich, Germany
| | - F Helmer
- Chair of Animal Welfare, Animal Behavior, Animal Hygiene and Animal Husbandry, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinaerstr. 13/R, D-80539 Munich, Germany
| | - A Schwarzer
- Chair of Animal Welfare, Animal Behavior, Animal Hygiene and Animal Husbandry, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinaerstr. 13/R, D-80539 Munich, Germany
| |
Collapse
|
9
|
koç N, Nalbantoğlu S. PAPAĞANLARDA DERMANYSSUS GALLİNAE KAYNAKLI KANİBALİZM. MEHMET AKIF ERSOY ÜNIVERSITESI VETERINER FAKÜLTESI DERGISI 2017. [DOI: 10.24880/maeuvfd.363443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|