Providing organic macro minerals and an elevated platform improved tibia characteristics, and increased locomotion and performance of fast- and slower-growing broilers

Effect of on-farm hatching and elevated platforms on behavior and performance in fast-growing broiler chickens

Alternative hatching systems compared to conventional hatchery-hatched systems showed positive effects on welfare of broiler chickens. In order to investigate an additional positive effect of elevated platforms, two hatching methods (on-farm [OH] vs. hatchery-hatched [HH]) and two environments from the first day onwards (with elevated platforms [enriched] vs. without elevated platforms [control]) were combined and investigated using a 2 × 2 factorial design. In three consecutive trials, the combination of the four treatments were repeated eight times each. One thousand six hundred fast-growing broiler chickens (Ross strain) were reared in a mixed-sex system. Chick quality was assessed at hatch and performance parameters and behavior parameters were measured during the entire rearing period of 35 d. For the statistical analysis, LME's and GLMM's were used depending on the data. In general, hatching system and housing environment showed no interaction. There were no differences in hatchability between treatment groups (p=0.93). However, OH chickens showed a higher body weight throughout the rearing period (all p<0.001). OH chickens had a lower body temperature than HH chickens (p=0.002) during the rearing period. OH chickens compared to HH chickens tended to show a higher usage of elevated platform at night (p=0.07). The enriched groups showed higher activity (p<0.0001), but no improved walking ability (p=0.82) than the control groups. The differences in performance and behavior were low between hatching systems and may be related to the short period of feed and water deprivation and the lack of long commercial processing and transportation procedures in the HH treatment group in our experiment. Overall, both on-farm hatching and elevated platforms can lead to an improvement of performance and activity parameters and, thus, an improvement of certain aspects of animal welfare but both factors do not seem to interact with each other.

Growth rate, either through genetics or diet, mainly determines the outcome concerning broiler welfare

There is a trend towards broiler production systems with higher welfare requirements, which often use a combination of factors to improve broiler welfare. This makes it difficult to entangle whether improvements are due to housing conditions, diet, genetics or a combination of these factors. Therefore, it remains unknown to what extent differences in welfare can be attributed to breed (i.e., genetics), growth rate (i.e., diet) or the interaction between the two. We compared fast- (Ross 308, R), medium- (Ranger Classic, RC) and slower-growing broilers (Hubbard JA757, H) receiving diets differing in balanced protein (BP) content (i.e., 80, 90 and 100%). We identified effects on behaviour, responses to behavioural tests and litter quality at three target body weights (TBWs, 0.2, 1.2 and 2.4 kg), and welfare scores and litter DM content at TBW 2.6 kg. The experiment had a 3 × 3 factorial design with four replicates (pens) per treatment (a total of 36 pens). We hypothesised that reducing the growth rate will improve the welfare of all breeds and that breeds will not differ in welfare if they have a comparable growth rate. Indeed, reducing the growth rate improved hock burn scores in all breeds. R broilers also had improved cleanliness scores and RC broilers improved gait scores. Reducing the growth rate increased the number of R broilers approaching a human and novel object and showing running behaviour in the free-space test, while it reduced the number of RC broilers approaching a human and showing comfort behaviour and did not affect behaviour in H broilers. In addition, litter quality was improved for R broilers (wetness and DM), while reduced for H broilers (DM) with reduced growth rate, and no effects of growth rate on litter quality were found for RC broilers. Thus, reducing growth rate (i.e., reducing BP in diets) improves welfare in all breeds, but breeds did respond differently concerning behaviour and litter quality, with more beneficial effects for fast-growing broilers compared to medium- and slower-growing broilers. Hardly any differences in behaviour, welfare scores and litter quality were found between breeds when they had a comparable growth rate (R80 vs RC100 and RC80 vs H100), except for R80 having better scores for cleanliness and gait scores (only males) and higher litter DM content compared to RC100. These findings suggest that growth rate, either through genetics or diet, is mainly determining the outcome concerning broiler welfare.

Light intensity preferences of broiler chickens is affected by breed, age, time of day and behaviour

Light is an important aspect of broiler husbandry and management as it influences behaviour and welfare. However, a lot remains unknown regarding broiler preferences for light intensities, especially for slower-growing broilers which are increasingly used in broiler production systems in the EU. We identified preferences of fast (F)- and slower (S)-growing broilers for intensities in relation to behaviour, age and time of day. Broilers were housed in pens with four sections, each having one intensity (0.2, 20, 50 or 1000 lx). Both breeds showed more active behaviours at higher intensities and more inactive behaviours at lower intensities. They preferred higher intensities when young and lower intensities when older, with S broilers preferring the lowest intensity more when older. They preferred higher intensities at the end and start of the light period, with F broilers preferring the highest intensity more when young and S broilers more when older. Thus, light intensity could be used to create functional zones within a broiler house for specific behaviours and light intensity programs could be adapted to age and time of day, taking into account breed differences. Furthermore, broilers were always present at each intensity, suggesting individual preferences and offering a choice might be beneficial for broiler welfare.

Effects of different environmental enrichment tools to improve behavior, welfare, and growth performance of broiler chickens

This study was performed to evaluate the effect of various environmental enrichment (EE) tools on broiler growth, welfare, behavior, carcass, and meat quality. A total of 300 commercial broilers were randomly divided into 05 treatments. The treatments include various EE tools such as perches, balls, hanging bottles, and laser lights placed for birds and a control group. The birds kept with perches and hanging bottles had the lowest feed intake, while the birds in the control group showed the poor feed conversion ratio compared to all EE treatments. Broilers raised under different EE were more active and exhibited frequent maintenance behavior (i.e., walking, jumping, running, wing flapping and aggressiveness) than the control group which spent more time in feeding and drinking. Moreover, the birds with EE had reduced incidence of toe injuries and footpad dermatitis than those in the control group. Birds reared with perches had higher meat lightness, whereas meat from the birds in the control group had lower cooking loss and shear force. It can be concluded that the use of various EE tools improved the welfare and behavior of the birds without affecting bodyweight of the birds. Furthermore, the use of hanging bottles and placing perches reduced feed intake and improved feed conversion ratio.

Tibia properties in broilers raised on their own commercial diets with different growth rates and sex during a 10-week rearing period

BACKGROUND

Genetic selection applied to broilers results in fast growth and an increase in meat yield. However, this situation causes welfare problems in broilers.

OBJECTIVES

The aim of this study is to determine the weekly changes in the tibia characteristics in broilers raised on their own commercial diets.

METHODS

In the study, 168 (84 female and 84 male) slow-growing (Hubbard-Isa Red JA) and 168 (84 female and 84 male) fast-growing (Ross-308) day-old broiler chicks were used. Six broilers from each genotype and sex group were weighed weekly and slaughtered to determine the tibia properties during the 10-week fattening period.

RESULTS

Fast-growing broilers had higher tibia weight and longer length, diaphysis diameter and medullary canal diameter than those of slow-growing broilers at the same age. In fast-growing genotypes, the cortical index was low only in the 2nd week, and Robusticity and Seedor indices were observed to be better throughout the whole fattening. The ash content of the total tibia in the fast-growing broilers was higher in all of the examined weeks except the 4th week and the 9th week of fattening than that in the slow-growing broilers. Although the amount of ash per unit body weight in the 1st week of fattening was higher in fast-growing broilers, this situation reversed after the 4th week. The level of all minerals examined in total tibia weight is high in fast-growing broilers, and they differed according to the fattening period.

CONCLUSIONS

When comparing tibia characteristics of two different genotypes fed their own commercial diets, the tibia structure was found to be stronger in fast-growing broilers compared to other genotypes at the same age, but slow-growing broilers were more prominent in terms of body weight. It was observed that the mineral density was higher in male broilers, except in the 1st week.

Fast- and slower-growing broilers respond similarly to a reduction in stocking density with regard to gait, hock burn, skin lesions, cleanliness, and performance

There is an increasing trend toward broiler production systems with higher welfare requirements. Breed and stocking density are considered key factors for broiler welfare that are often specified as criteria for such higher welfare systems. However, it remains unknown how slower-growing broilers respond to a reduction in stocking density with regard to their welfare and performance, and whether this response differs from fast-growing broilers. Therefore, we compared fast- (F) and slower-growing broilers (S) housed at 4 different stocking densities (24, 30, 36, and 42 kg/m2, based on slaughter weight) and measured their welfare scores (i.e., gait, footpad dermatitis, hock burn, skin lesions and cleanliness), litter quality and performance. The experiment had a 2 × 4 factorial design with 4 replicates (pens) per treatment (32 pens in total). Thinning (15%) was done in a 50/50 male/female ratio at 38 (F) and 44 (S) d of age (estimated body weight of 2.2 kg). We hypothesized that breeds would respond differently to a reduction in stocking density. Contrary to our hypothesis, only one interaction between breed and stocking density was found on footpad dermatitis, indicating that fast- and slower-growing broilers generally showed similar responses to a reduction in stocking density. F broilers showed a steeper decline in the prevalence of footpad dermatitis with reducing stocking density compared to S broilers. Broilers housed at lower stocking densities (24 and/or 30 kg/m2) showed improved welfare measures, litter quality and performance compared to those housed at higher stocking densities (36 and/or 42 kg/m2). S broilers had better welfare scores (gait, footpad dermatitis and skin lesions), litter quality and lower performance compared to F broilers. In conclusion, reducing stocking density improved welfare of both F and S broilers, but more for F broilers in case of footpad dermatitis, and using S broilers improved welfare compared to F broilers. Reducing stocking density and using slower-growing broilers benefits broiler welfare, where combining both would further improve broiler welfare.

Increased duration of laser environmental enrichment increased broiler physical activity and pen-wide movement without altering tibia measurements

Inactivity and leg disorders negatively impact broiler welfare. Enrichment designed to increase barn complexity may encourage physical exercise. The study aim was to implement a second-generation laser enrichment device, previously shown to increase broiler activity, for extended periods of time and to measure behavior and tibia quality. A total of 1,360 Ross 708 broilers in 40 pens of 34 were assigned to laser enrichment or control (no laser enrichment) for 49 d. Seventy focal birds were randomly selected on d 0 for individual behavior analysis. Laser-enriched birds were exposed to 6-min laser periods 4 times daily. A 3-min novel object test was performed on all pens and tonic immobility was induced on 1 bird/pen on wk 1 and 6. Focal bird time budget and walking distance and pen-wide laser-following behavior and movement were obtained during laser periods d 0 to 8 and 1 d/wk through wk 7. Right tibias were collected from focal birds on d 49 for dual energy x-ray absorptiometry and bone breaking analysis. Time spent active during laser periods was increased on d 3, 6, and 8 and wk 2 to 3 in laser-enriched vs. control focal birds (P = 0.04). Time at the feeder was increased in laser-enriched focal birds on d 0, 3 to 4, and 8 and wk 2 and 4 (P < 0.01). Distance walked during laser periods was increased in laser-enriched focal birds on d 1, 3 to 5, 8, and wk 2 compared to the control (P < 0.01). Pen-wide movement was increased on d 0, 2, 4 to 8, and wk 1 to 5 and 7 in laser-enriched vs. control birds (P < 0.01). More laser-enriched broilers were within 25 cm of the novel object at 1 min 30 s than the control (P = 0.03), and latency to approach the novel object was reduced in both treatments at wk 6 compared to wk 1 (P < 0.01). Tonic immobility duration was increased by 123 s on wk 6 compared to wk 1, regardless of treatment (P < 0.01). Daily laser enrichment for extended periods increased bird activity without inducing fearfulness or altering tibia measures.