About the book
In 1945, the American grocer A&P (Atlantic & Pacific Tea Company) organized the first of its “Chicken of Tomorrow” contests with the national finals held in 1948. For the finals, breeders submitted a case of 30 dozen hatching eggs to an Eastern Shore hatchery, where the eggs were hatched and the offspring fed until they reached market weight and then slaughtered. Broilers were judged on several factors including growth rate, feed conversion efficiency, and the amount of meat on breast and drumsticks. Because the original purpose of most birds was to grow large quickly, breeders used weight as the primary selection criterion. Genetic line companies found that weight was moderately heritable, with 20-40% of the trait genetically controlled. Though simple, this selection process helped improve broiler breeder performance across generations. Market forces have changed selection criteria over the years. A more integrated and consolidated industry learned that weight and growth rates alone could not be the only selection criteria considered. This was particularly true as feed costs increased. Today, feed accounts for 65-70% of the input cost for a broiler. Nowadays, a newly hatched chick increases its body weight by 25% overnight and 5400% by 35 days, to reach an average body weight of 2,273 grams.
This astonishing performance of the modern chicken comes from: 1) intensive selection for growth rate, 2) meticulous attention to health and husbandry, and 3) advances in feed formulation, matching the nutrient contents of the feed with the nutrient requirements of the bird. That is why gut health and feed efficiency are so crucial for broiler chickens since feed efficiency is considered “the money saver”. In today’s broiler industry, subclinical forms of coccidiosis or necrotic enteritis are often financially more devastating than acute, short-term infections. Likewise, dietary factors that modulate the immune system and gut microbiota should be considered when formulating diets and managing feeding practices. As the growth period is progressively shortened and feed efficiency continuously improved, the health care and nutrition of the bird are becoming more demanding. This makes it more important to pay attention to the minute changes that occur in the gut, which are often overlooked because the damage is subtle and usually characterized by microscopic changes in the mucosal layer.
The purpose of this book is to present updated information on this fascinating industry in the areas of management, nutrition, health, diseases, and hatchery and incubation.