Nutritional means to enhance skeletal development in pullets and subsequent effects on layers productivity, bone health and welfare

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Canadian supply managed egg production system has 1,021 registered egg farms with a total of approximately**20 million layers and contributes $1.28B to Canada's GDP. Bone health manifested as osteoporosis is a**persistent problem in layers under different housing systems with detrimental effects on flock productivity and**egg shell quality and thus profitability. Bone quality is influenced by genetics, housing system environment and**nutrition. However, the trends of decreased sexual maturity without concurrent refinement in mineral content**of the feed may juxtapose with the hen's increased capacity to produce more eggs with less feed (more calcium**output and less input) such that bone mineralization is impaired during rearing and /or lay cycle giving rise to**mortality and morbidity stemming from metabolic calcium insufficiency and osteoporosis. Studies to improve**hen skeletal health often focus on manipulating environment and nutrition during the laying. However, as**pullets develop a mature frame size by 12 weeks of age followed by formation of medullary bone around**sexual maturation, supplementing calcium during active lay may be too late to improve bone density and**quality. Our hypothesis is that proper skeletal development is essential for high levels egg production and**challenges of alternative housing for modern layers. Studies will be conducted to investigate the role of feed**structure (manipulation of fiber fraction and limestone particle size) and optimal calcium, phosphorous and**vitamin D supplementation on skeletal development pullets and subsequent effects in productivity, egg shell**quality, livability and welfare in hens. This is a timely research and will provide valuable information to the**egg industry in light of the forthcoming changes in Canadian hen housing systems. The project will employ a**variety of experimental, statistical, and analytical techniques thus providing excellent opportunities for the**training of highly qualified personnel. Specifically, the research project will support training of 1 PhD, 2 MSc**by thesis, 1 MSc by coursework, 2 undergraduate students and 1 Postdoctoral Fellow as well as a technician.