Early post-hatch feeding and drinking behavior and body weight development in white and brown layer chickens.

Effects of early post-hatch feed and water deprivation on eating and drinking behavior and body weight development have been mostly investigated in broiler chickens. However, little is known about these aspects in layer chickens. This study investigated the eating and drinking behavior of white (Dekalb White) and brown (Lohman Brown Classic) layer chickens early post-hatch, as well as the feed and water intake and body weight development. A total of 352 in-ovo sexed female eggs on day 18 of incubation were allocated to 16 pens (8 pens per strain, 22 eggs per pen) and hatched in the pen. The first eating and drinking moment, and the eating and drinking frequency and duration in the subsequent 12 h period were determined. Feed and water consumption and body weight were measured every 6 h from hatch to 96 h of biological age. White layer chickens started eating and drinking on average at 8 and 34 h post-hatch, whereas brown layer chickens began at 5 h and 26 h, respectively. During the first 12-96 h post-hatch, each chicken consumed approximately 15 g of feed and 25 g of water on average. White layer chickens consumed more water than brown layer chickens, while feed intake did not differ. Both strains spent approximately 2 % of their time eating and drinking within the first 12 h after their first eating and drinking post-hatch. White layer chickens exhibited a higher drinking frequency and longer drinking duration than brown layer chickens, whereas hatch moment did not affect these variables. Body weight of both strains decreased during the first 30 h post-hatch and returned to its initial value at approximately 60 h post-hatch. It can be concluded that layer chickens start eating and drinking soon after hatching, but the frequency of eating and drinking remains low thereafter. Layer chickens initially lose body weight post-hatch even when feed and water are available immediately post-hatch. The exact timing of the first eating and drinking event and subsequent drinking behavior appears to be strain dependent.