Effects of early access to feed and water in hatchers on growth performance in broiler chickens

Conventional hatchers do not provide feed or water to chicks during hatch, which may negatively affect chick development, especially in early hatchlings subjected to prolonged feed deprivation due to biological variation in hatch time. This study aimed to evaluate the effects of early access to feed, water and a synbiotic product on performance, caecal microbiota development, organ development, intestinal morphology, total serum immunoglobulin (Ig) Y and antibody response to vaccination in Ross-308 chickens. A total of 330 chicks hatched in a specialised hatcher were divided into three hatch treatment groups: access to feed, water and synbiotic additive (PS); access to feed and water (PosC); no access to feed and water (NegC). Ten birds per hatch treatment were euthanised for organ sampling at placement, and the remaining 300 chicks were randomly allocated to 30 pens. All chicks received feed and water, and half the chicks in each treatment group received the synbiotic additive for 3 consecutive days (giving three hatching treatments and two postplacement treatments). All chicks were vaccinated against avian pneumovirus (APV) at 10 days of age. Blood sampling was performed weekly on three focal birds per pen for analysis of total serum IgY and antibodies to APV. Organ sampling was performed on days 11 and 32. Feed intake (FI) and BW were recorded weekly. The NegC group exhibited reduced early growth and lower FI throughout the study. At 25 days, they also demonstrated an inferior feed conversion ratio (FCR) compared with the other groups. At 4 and 25 days chickens that did not receive any postplacement treatment, None had superior FCR compared to those receiving PS also postplacement. There was also an effect of postplacement treatment where the None group weighed more compared to the PS group on almost all occasions. The NegC group had higher concentrations of IgY in serum compared to the PosC group at 3 days of age, an effect that remained a tendency until 25 days of age. No differences between treatments were found for antibody responses to APV vaccination. Some differences in relative weights of digestive organs between hatching groups were detected at the end of study, while no persistent effects on caecal microbiota composition were observed. In conclusion, delayed access to feed and water had adverse effects on productivity traits, lasting throughout the study. These findings warrant further validation in a practical context with higher stocking densities and pathogen loads.