ABSTRACT
The priority for producers, breeding and feed companies is to increase egg production. Continuous improvement in egg number has been initially obtained by selecting hens for early sexual maturity and improved peak of production. However, nowadays, the priority of breeding companies is to increase persistency in lay and maintain egg quality in older hens (Bain et al., 2016). Selection of egg persistency, combined with improvement in eggshell and internal egg quality in hens at older ages, have enabled egg production to be extended to more than 80 weeks of age (Dunn, 2013; Pottguetter, 2015). Currently, the aim is to extend the laying cycle of commercial flocks to 100 weeks to get more than 500 eggs in a single cycle without moult. This corresponds to exportation of more than 26 kg of eggs (about 14-fold the hen’s body weight) and more than 1 kg of calcium (3 kg of eggshell).
