Patricia Y. Hester

Beak trimming egg-laying strains of chickens

Bird behaviour, production, physiological measurements of stress, and pain as indicated by neural transmission in, and anatomy of the trimmed beak have been used as criteria to determine if beak trimming compromises bird well being. In addition, the welfare of those hens that are pecked by beak-intact hens has been evaluated. The welfare of a flock is assessed by mortality, incidence of cannibalism, feathering, and flock behaviour such as fearfulness or nervousness. Disadvantages of beak trimming include short-term and perhaps long-term pain, and short-term stress following beak trimming. Because feeding behaviour must adapt to a new beak form, a birds ability to consume feed is impaired following beak trimming. Welfare advantages include reduced pecking, feather pulling, and cannibalism; better feather condition; less fearfulness and nervousness; less chronic stress; and decreased mortality. It appears that the welfare disadvantages are applicable to individual birds whose beaks are trimmed, while the welfare advantages are more applicable to the interactive flock. Behavioural evidence suggests that primary breeders of egg laying strains can select for more docile birds and minimize the need to beak trim. Therefore, using genetic stocks that require little or no beak trimming is the most desirable approach. However, under certain management systems (e.g., exposure to high intensity natural lighting) and with some genetic stocks, beak trimming is needed to prevent feather pecking and cannibalism. When employed, beak trimming should be conducted at 10 days of age or younger by trained personnel.

Comparison of two lighting regimens and drinker cleaning programmes on the performance and incidence of leg abnormalities in Turkey males

Turkey males subjected to a low intensity step-down (LISD) lighting programme showed significantly heavier body weights after 20 weeks of age and significantly better feed conversions after 14 weeks of age compared with males reared in a high intensity step-up lighting (HISU) programme. Although both nonchilled and chilled carcase weights were higher, the dressing percentages were lower for males of the LISD lighting regimen. Males of the HISU lighting programme had significantly fewer leg abnormalities, shorter tarso-metatarsi, lighter drumstick weights, and lighter tibia weights. Males on the HISU lighting programme from 15 to 19 weeks of age had larger testes; however, after 20 weeks of age they were larger in males on the LISD lighting regimen. Cleaning and disinfecting the drinking troughs daily rather than weekly had no effect on any production variable measured.

The Effect of Cooled Perches on Immunological Parameters of Caged White Leghorn Hens during the Hot Summer Months

The objective of this study was to determine if thermally cooled perches improve hen immunity during hot summer. White Leghorn pullets at 16 week of age were randomly assigned to 18 cages of 3 banks at 9 hens per cage. Each bank was assigned to 1 of the 3 treatments up to 32 week of age: 1) thermally cooled perches, 2) perches with ambient air, and 3) cages without perches. Hens were exposed to natural ambient temperatures from June through September 2013 in Indiana with a 4 h acute heat episode at 27.6 week of age. The packed cell volume, heterophil to lymphocyte (H/L) ratio, plasma concentrations of total IgG, and cytokines of interleukin-1β and interleukin-6, plus lipopolysaccharide-induced tumor necrosis factor-α factor were measured at both 27.6 and 32 week of age. The mRNA expressions of these cytokines, toll-like receptor-4, and inducible nitric oxide synthase were also examined in the spleen of 32 week-old hens. Except for H/L ratio, thermally cooled perches did not significantly improve currently measured immunological indicators. These results indicated that the ambient temperature of 2013 summer in Indiana (24°C, 17.1 to 33.1°C) was not high enough and the 4 h heat episode at 33.3°C (32 to 34.6°C) was insufficient in length to evoke severe heat stress in hens. However, cooled perch hens had a lower H/L ratio than both air perch hens and control hens at 27.6 week of age and it was still lower compared to control hens (P < 0.05, respectively) at 32 week of age. The lowered H/L ratio of cooled perch hens may suggest that they were able to cope with acute heat stress more effectively than control hens. Further studies are needed to evaluate the effectiveness of thermally cooled perches on hen health under higher ambient temperatures.

Relationship of high intensity step‐up lighting to bone ash and growth plate closure of the tarso‐metatarsus in Turkeys

The reduced lameness observed in turkeys reared in a high intensity step-up (HISU) lighting programme as compared to a low intensity step-down (LISD) lighting regimen cannot be explained by differences in the inorganic matrix of the bone, because the proportions of bone ash, bone ash calcium, and bone ash phosphorus did not differ between lighting programmes. At 17 weeks of age, there was a significant difference in the proportion of closed growth plates in males reared on the HISU programme rather than on LISD lighting. These results support the hypothesis that HISU lighting reduces lameness by promoting earlier growth plate closure of long bones.

Breeder Hen Influence on Nutrient Availability for the Embryo and Hatchling

Because the majority of the avian embryonic development occurs outside of the hen’s body, the egg when laid must be packaged with all of the essential nutrients of fat, protein, carbohydrates, vitamins, and minerals required for development during incubation and survival immediately posthatch. The hen deposits these nutrients in the yolk, albumen, and shell of the egg as it is being formed in her reproductive tract. The sources of these nutrients are derived from the feed that the hen is consuming during egg formation and her body reserves. During incubation, the embryo retrieves the nutrients from egg components for development. This review highlights how the female chicken sequesters nourishment from her feed and body and places these nutrients into her egg so that they are available to her offspring during embryogenesis and immediately posthatch. The influence of breeder hen diet on the embryo and the chick posthatch will also be discussed.

Enrichments in Cages

Surveys indicate that consumers want animals that are used for food to be able to express their natural behaviors. Cages for laying hens that are furnished with a nest, perches, nail trimmers, and a scratch pad/foraging area provide opportunities for hens to perform instinctive behaviors that they otherwise could not do at all or not very easily in the barren conventional cage. To meet consumer demand, the egg industry worldwide is beginning to use enriched cages; however, the design of the enriched cage is not without problems. Strategies for improvement include perch redesign to reduce keel bone damage, improving the scratch pad or foraging area to reduce food safety concerns related to fecal contamination of eggs, finding a suitable and practical substrate that encourages dustbathing so as to improve plumage condition, and identifying the enrichment needs of caged pullets.

Preventive Measures for Avoiding the Deleterious Effects of Heat Stress on Egg Production and Quality

Egg-laying poultry are located worldwide in climates where high temperature extremes can occur at some point during the egg production cycle. Poultry can tolerate and adapt to temperatures up to 25°C; temperatures above this level can lead to heat stress. Egg production, egg weight, and quality of eggs are detrimentally affected by high temperatures. Hens adapt by initiating coping mechanisms including panting, wing spreading, lowering their metabolism, reducing feeding activity, drinking more water, and releasing stress hormones. The farmer provides heat protective measures, such as proper house design and orientation with adequate ventilation, feeders, and drinkers. The nutritionist formulates high nutrient density diets enriched in fat, essential amino acids, vitamins, and minerals to compensate for the lost appetite of heat stressed hens. Water is used as medium to supply electrolytes, vitamins, and bicarbonate in heat stressed hens experiencing marginal deficiencies.

Effects of Temperature and Storage Conditions on Eggs

Abstract The table egg is a perishable food item with a limited shelf life. The fertile hatching egg also deteriorates in quality with age. Prolonged storage of eggs leads to the escape of water and carbon dioxide through the pores of the shell increasing albumen pH causing the egg white to become less viscous. To retain quality and minimize the opportunity for pathogen growth, both table and hatching eggs are collected frequently and stored in a humidified cooler. Current regulation in the United States requires that the ambient temperature of processed table eggs be maintained at 7.2°C (45°F) or below. Chicken hatching eggs are stored at 18°C (65°F). Intervention strategies to counter the decline in hatch rate with extended storage include a cooler storage temperature with eggs positioned with the small end up, and flushing nitrogen into plastic bags containing eggs that are subsequently sealed.