Dual-energy X-ray absorptiometry can be used as a noninvasive tool to monitor the skeletal integrity of live birds. A pDexa X-ray bone densitometer was used to determine bone mineral densities (BMD) of the left tibia together with the fibula and the humerus of live, unanesthetized birds. Densitometry effectively detected changes in bone integrity of live birds fed varying levels of dietary calcium. Hens consuming 1.8, 3.6, or 5.4% dietary calcium had BMD of 0.147, 0.157, and 0.176 g/cm2 (SEM = 0.005), respectively (linear effect, P < 0.001). Likewise, bone ash weight, breaking force, stress, modulus of elasticity, and eggshell traits also increased linearly in response to increased calcium in the diet (P < 0.05). Densitometric live scans for BMD were positively correlated (P < 0.001) with bone breaking force (r = 0.65) and bone ash (r = 0.77). We also monitored BMD in live Leghorn and broiler females during their life cycle. The tibial BMD of White Leghorns and broilers increased from 15 to 65 wk of age with the BMD of the broiler tibia increasing at a greater rate than that of the Leghorn tibia (line x age interaction, P < 0.0001). A precipitous drop in BMD occurred during an induced molt of Leghorns subjected to 10 d of feed withdrawal. Our long-term goal is to improve skeletal integrity in egg-type chickens by genetic selection for improved BMD. By crossing a broiler with an egg-laying line, an F2 resource population of birds has been developed to identify quantitative trait loci influencing BMD in chickens.

Osteoporosis, a progressive decrease in mineralized structural bone, causes 20 to 35% of all mortalities in caged White Leghorn hens. Previous resear

Discoveries in behavior and welfare science have improved the health and well-being of egg laying flocks of chickens. The objectives of this review are to highlight research findings in genetics, health, environment, molting, morphological alterations, euthanasia, handling during depopulation, transportation, and harvesting to improve poultry welfare and to provide examples of additional opportunities to continue this progress. Although selection for disease resistance has improved the welfare of birds, use of genetic marker technologies may eventually advance the selection of healthier birds with fewer metabolic disease and cannibalistic tendencies. Animal health and welfare have been improved through development of vaccines, establishment of stringent biosecurity measures, and training of animal caretakers. Industry is currently making adjustments in bird space allocations to allow for less crowded conditions. Continued research in molting shows promise to avoid feed withdrawal regimens for laying hens. Beak trimming by trained personnel improves livability, reduces cannibalism, and should be used when nonaggressive strains are unavailable and when light intensity cannot be controlled. Extension specialists and veterinarians provide information on proper procedures for euthanasia. New systems for euthanasia of spent hens are being implemented by egg producers. New opportunities exist for use of enrichments in production facilities to offer environmental complexity. Further research on how sound and odors affect birds could provide new avenues for improving production systems.

Life cycle changes in bone mineralization and bone size traits of the tibia and humerus were evaluated in commercial male and female broilers using d

The public wants assurances that animals used for food are raised humanely. Conventional cages for egg laying hens do not meet hen's behavioural needs, but cages have potential advantages such as improved liveability and respiratory health because of less aerial ammonia and dust as compared to non-cage systems. Providing amenities to cages might be a compromise that allows hens to reap some of the advantages of conventional cages and also better meet their behavioural needs. This review focuses on the perch as a furnishing and how its design and addition to the cage can affect welfare and production efficiencies of egg laying strains of chickens. Hens should have access to perches because of their high motivation and preference for perching. At night, hens like to perch at the same time which requires a straight perch space of 12 and 15 cm for White Leghorn and brown hybrids, respectively. Besides meeting a behavioural need, perches in cages improve bone strength, but the improvement is not great enough to prevent adult keel fractures and deformities. Perch access improves feather quality for the back but not for other feather tract areas. Foot pad, toe, and nail health are often improved with perch access in cages of smaller group sizes. With the exception of dirty and cracked eggs, perches installed in cages do not deleteriously affect hen performance. Commercial perches are available in different shapes (e.g., round, circular, or mushroom) and compositions (e.g., wood, plastic, or metal). There is no perfect perch relative to its material composition or shape. Wooden perches offer a rougher texture but harbour mites in crevices. Future research should concentrate on perch redesign that avoids slippery surfaces allowing hen's feet to better grip the perch, prevents keel fractures, is easily cleaned, and does not harbour parasites or pathogens.

Beak trimming egg-laying strains of chickens - Volume 59 Issue 4 - P.Y. Hester, M. Shea-Moore