Commercial Poultry Nutrition
http://www.amazon.co.uk/Commercial-Poultry-Nutrition-S-Leeson/dp/190476178X/ref=sr_1_1?s=books&ie=UTF8&qid=1340006368&sr=1-1
Nutrient Requirements of Poultry
http://www.amazon.co.uk/Nutrient-Requirements-Poultry-Domestic-Animals/dp/0309048923/ref=sr_1_1?s=books&ie=UTF8&qid=1340006462&sr=1-1