This study evaluated the influence of hatching time on physiological status of 40 newly hatched broiler chicks at the end of incubation.Four batches (300 eggs/ batch)of Ross 308 eggs were incubated in two small scale custom built incubators (Petersime NV).The hatching time of focal eggs was monitored using video cameras.Following the commercial practice of take-off (when all chicks are reruoved from the machine once the majority of the chicks have hatched),focal chicks were assessed using the standard chick quality scoring method and physiological parameters: body weight,organ (heart,liver and stomach)weights and plasma corticosterone level.The time of take-off minus the individuals hatching time gave the duration each focal chick spent waiting in the machine.The focal chicks waited between 7.5 to 45.3 hours with the majority of chicks waiting in the machines for 20 t0 30 hours after hatch.Positive association of heart weight with chick weight (r = 0.6,P =0.001)and relative stomach weight with waiting time (r = 0.6,P =0.001)were found.In addition,chick weight is significantly associated (r=0.9)with egg weight (P<0.001 )and waiting time (P = 0.02).Furthermore,there was a positive correlation between plasma corticosterone levels and waiting time (r=0.6,P =0.03).Specifically,chicks that hatched early had higher corticosterone levels than chicks that hatched later which indicate that chicks might be more stressed the longer they waited.We conclude that it is important to shorten the hatch window in order to minimize the number of chicks that experience a long wait for take-off and hence heightened stress,which may be due to challenging environmental conditions or an extended period of feed and water deprivation.
Tong Q Eterradossi N Garain P McGonnell I.M Demmers T Romanini C.E Bergoug H Roulston N Exadaktylos V Bahr C Berckmans D Guinebretière M
The Royal Veterinary College,Hawkshead Lane,North Mymms,Hatfield,AL97TA Hertfordshire,United Kingdom Anses,Ploufragan-Plouzane Laboratory,Avian and Rabbit Virology-Immunology-Parasitology Unit,BP 53 Pl Research and Development,Petersime N.V.,Centrumstraat 125,B-9870 Zulte(Olsene),Belgium Division M3-BIORES:Measure,Model & Manage Bioresponses,KU Leuven,Kasteelpark Arenberg 30-box 2456,B- Anses,Ploufragan-Plouzane Laboratory,Avian and Rabbit Epidemiology and Welfare Unit,BP 53 Ploufragan