Spatial Variability of External Egg Quality in Vertical Naturally Ventilated Caged Aviaries

External egg quality is an essential parameter of egg production as it relates directly to economic losses. This study evaluated the spatial variability of external egg quality in five naturally ventilated caged vertical aviaries. Differences caused by bird age and thermal and luminous variability within aviaries during winter and summer were analyzed. Data on aviary air temperature, relative humidity, light intensity, and external egg quality were collected at evenly distributed points along the aviary length within three levels of cages. The experimental design was completely randomized in a factorial scheme. In the summer, the highest air temperature and lowest relative humidity were found in central cages, mainly in upper center cages; hens produced eggs with a lower weight and shape index in this area. Similar results were obtained in the winter. In the summer, eggs with lower shell weight and thickness were also produced by hens housed in the central cages, but in the winter, the opposite result was obtained. This study of the spatial variability of external egg quality proved efficient in detecting areas within an aviary with poor quality eggs; improvements to design and management in these areas could help management improve production efficiency and contribute to a sustainable egg supply.

Effect of cooled perches on the efficacy of an induced molt in White Leghorn laying hens previously exposed to heat stress

This study examined the effect of water-chilled perches on hen production and physiological responses to induced molt during elevated temperatures. A total of 288White Leghorns at 82 wk of age were housed in 36 cages of 6 banks. Each bank was assigned to 1 of 3 treatments: cooled perches, air perches, and no perches. The hens were subjected to 2 heat episodes during their first laying cycle at week 21 to 35 and week 73 to 80, respectively. The hens were subjected to a 28 D nonfasted molting regimen starting at 85 wk of age. Cyclic heat of 32°C (6:00 am to 6:00 pm) was applied daily during the molting period. After molt, hens were returned to a layer diet and housed under thermoneutral condition. Two birds per cage were monitored for BW change during molt. Egg production was recorded daily. Feed utilization was measured during molt at 86 and 88 wk of age. Egg weight and eggshell traits were examined at 84 wk (pre-molt) and post-molt at 92, 96, and 104 wk of age. Rectal temperature and blood samples were collected from 2 birds per cage at the end of molt. Blood samples were used for determining heterophil/lymphocyte ratio, corticosterone, and thyroid hormones. Plumage condition was examined at 22 wk post-molt. Compared to control and air perch hens, cooled perch hens had higher feed usage and greater BW loss, lower heterophil/lymphocyte ratios (P < 0.05) with no difference in thyroid hormones and corticosterone at the end of molt. Cooled perch hens also had higher egg production beginning at 98 wk of age (Ptreatment*age < 0.0001) than control hens and sometimes the air-perch hens. Cooled perch hens had higher rectal temperature than control but not air perch hens at end of molt. Moreover, cooled perch hens had better breast feather scores than air perch hens but worse vent plumage (P ≤ 0.05) than both control and air perch hens. These results indicate that the provision of cooled perches assists hens with better adaptation to stressors, such as induced molt plus heat exposure, resulting in improved post-molt egg production.

Effects of choice feeding and lower ambient temperature on feed intake, growth, foot health, and panting of fast- and slow-growing broiler strains

Effects of lowering ambient temperature in the second half of the growth period were studied in 2 broiler strains with different genetic potential for growth (Ross from 1972 and 2004) when given ad libitum access or pre-mixed increasing proportion of whole wheat in their diet. A total of 48 groups of day-old broilers (n = 64) from the 2 strains were housed as hatched in 48 pens in 4 houses and slaughtered at 6 wk of age. Half of the groups had access to pelleted feed pre-mixed with increasing proportion of whole wheat, the other half had access to pelleted feed and whole wheat in separate troughs. Ambient temperature from 28 d of age was either 21 or 15°C. The fast-growing strain had greater (P < 0.001) live weight throughout (mean slaughter weights 2.6 (±0.014) kg and 1.0 (±0.006) kg). When given a choice, the fast-growing strain consumed a lower (P ≤ 0.004) proportion of whole wheat in their diet in weeks 5 and 6 (20 and 26 (±0.9) % whole wheat), and the slow-growing strain chose a higher (P < 0.001) wheat proportion (45 and 56 (±1.7) %) than the pre-mixed inclusion of 25 and 30%, respectively. The slow-growing strain grew slightly faster in the colder ambient temperature, and slower when given a free choice of whole wheat. Both strains drank more water per feed consumed in the warmer ambient temperature treatment. Foot pad dermatitis, only seen in the fast-growing birds, had a higher occurrence in the colder and in the choice feeding treatments. Gait scoring on day 34 showed perfect gait in more than 85% of the slow-growing and less than 1% of the fast-growing birds. Activity was higher and panting levels were lower in the slow-growing strain (P < 0.001) toward the end of the growth period, with no effect of the temperature treatment on panting. Slow-growing strains increase their energy intake, and fast-growing strains increase their protein intake when given a choice.

"Cracking" into the debate about laying hen housing

Livestock production systems have faced social pressures related to animal welfare; the laying hen industry also has faced changes in governing regulations/policies. This study employs experimental data to evaluate 3 confinement-housing systems: standard cages with no perches, cages with standard perches, and cages with cooled perches. Based on the cost-benefit analysis conducted of revenue less feed costs, operators are expected to have revenue, after covering feed costs, which could contribute to installation and maintenance of standard and/or cooled perches. Thus, egg producers may be able to use caged housing that incorporates perches profitably, depending on the final costs of such a system.