Review: Current challenges in poultry nutrition, health, and welfare.

The poultry industry has benefited greatly from advances in genetics, nutrition, housing and management strategies. Geneticists have made welfare and health traits important components of selection programs, and in general, modern, high-producing poultry are healthier than 30 years ago. However, increased productivity means that the birds are closer to their physiological limits, and nutrition, environment and management have become increasingly important. The move away from in-feed antibiotic growth promotors has resulted in challenges in maintaining gut health and consequently, bird performance. However, as the industry adapts to production without the use of antibiotic growth promotors, long-term benefits may be realized due to a reduction in antimicrobial resistance. Intensive selection for meat yield and efficiency are associated with an increased risk of muscle myopathies that affect bird health and meat quality. As genetic selection increased broiler production traits, it became necessary to restrict parent stock nutrient intake in order to prevent excessive muscle and fat deposition, reduce metabolic disease, and maintain ovarian control. With continued selection for broiler production traits, the degree of restriction implemented has become a welfare issue. Additionally, recent research suggests that highly efficient broiler lines may have limited fat deposition and therefore energy reserves to support sexual maturation and egg production, especially if typical broiler breeder BW targets are maintained. A re-examination of broiler breeder feeding programs is necessary to maintain productivity and welfare. Modern laying hens are capable of laying cycles in excess of 100 weeks of age. This has reduced the use of stress-inducing forced molting programs and reduces the total number of hens needed to meet the demand for egg production. The important role of the skeletal system in eggshell deposition demands that skeletal development during rearing be carefully managed to avoid shell and skeletal problems at the end of the production cycle. As the production potential of modern poultry continues to increase through genetic and genomic selection, even greater care must be paid in order to maintain bird health and welfare. The poultry industry has successfully faced many challenges in the past and is likely to overcome the existing challenges as well.