GROWTH AND BEHAVIOR OF NEWLY-HATCHED CHICKS WITH AND WITHOUT YOLK SACS

This experiment was designed to study effects of feed sources differin g in energy and protein levels as well as yolk removal on behavior, bo dy weight, and gastrointestinal tract (GIT) growth and contents in mal e chicks from a commercial white egg-layer stock. Yolk sacs were surgi cally removed (YR) from half of the chicks while the other half remain ed yolk-intact (YI). From Days 0 to 6, all chicks were offered a choic e of residual yolk (Diet Y) or mash (Diet A) and beginning on Day 6, a ll chicks were fed Diet A. Throughout the experiment, the YI chicks we re heavier than YR chicks, but by Day 13, the YR chicks gained proport ionately more body weight. The only difference in GIT data was the wei ght of chyme at 21 days of age, which was higher in the YI chicks than in YR chicks. Behavior results showed that YI chicks stood more while YR chicks rested more throughout the experiment. Experiment 2 consist ed of 4 groups: YI chicks fed Diet E (mash feed higher in energy and p rotein), YI chicks fed Diet A (mash feed lower in energy and protein), YR chicks fed Diet E, and YR chicks fed Diet A. Dissections on Days 6 , 13, and 20 quantified effects of diet and/or treatment on growth and contents of GIT segments. On Days 13 and 20, there were no difference s due to diet of treatment for GTT data except for the consistent diff erence due to diet for relative weight of the gizzard, with a higher v alue in the Diet A chicks. Similar to results from Experiment 1, on Da y 13 YR chicks gained relatively more body weight than YI chicks fed D iet A. Also consistent with Experiment 1, of chicks fed Diet A, the YI chicks stood more than the YR chicks.