pullet, breeder, nutrition


During the last six to seven decades, broilers have been successfully selected for maximum growth and feed efficiency (Zuidhof et al., 2014). Modern fast-growing broilers reach a body weight of 2.0 to 2.5 kg in 35 to 45 days with an average daily growth of 55 or more gram a day (Augère-Granier, 2019). In a study with different broiler strains representative of broilers in 1957 or 1978 were compared with a broiler strain from 2005 (Zuidhof et al., 2014). The 2005 strain showed, over a 56-day growth period, a 4.6 times higher growth rate and a 50% lower feed conversion ratio. Besides the improvement in growth performance of broilers, body composition has changed as well during the last sixty to seventy years. The selection on increased feed efficiency and growth rate, and decreased body fat content has not only affected the offspring but also the parent stock (broiler breeders) (van Emous, 2015). Although the poultry breeding companies have worked to maintain or even increase the rates of egg production and hatchability (Laughlin, 2009), achieving these potentials at the broiler breeder farm level on a consistent level has proven to be more challenging (Renema et al., 2013). Therefore, optimization of the diet and feeding management is necessary to achieve maximal reproduction (van Emous, 2015). The main objective during the rearing phase is to produce pullets of ideal weight, uniformity, condition and stage of sexual maturity. The main objective during the laying phase is producing fertile, good quality and clean eggs (van Emous et al., 2020).