Effect OF Shell Thickness on Quail Chick pip-out at Hatching

Abstract Text: Economic losses incurred by farmers when chicks could not pip out at hatching is a major consideration in commercial hatchery operations.  The inability of chicks to come out of an egg shell unassisted has its attendant consequences on the survival and livability of Quail chicks. Aside from genetic effect, age and nutritional status of the hen, egg shell thickness is also a major factor. This study was conducted to determine the effect of egg shell thickness on the on the ability of Quail chicks to pip out of the shell at hatching. A total of 593 fertile eggs collected from a farm located in Jos, Plateau State in the Savannah region of Nigeria, were incubated and hatched. The eggs were weighed and linear measures were taken using digital weighing scale and caliper. The measured variables include, egg weight, egg length, egg width, shell thickness, vertical and horizontal circumference while shape index, egg density, egg volume, egg surface area and surface area to volume ratio were computed.  All statistical analyses were done using JMP statistical software for the descriptive statistics, correlation, model fitting and logistic regression.  After incubation, 570 eggs hatched and eggs that were not hatched (23) were opened up to determine if the chicks fully developed but could not pip out unassisted.  The result revealed that there was no statistical difference (P>0.05) in the mean of all variables studied.  A binary logistic regression of the shell thickness on hatching status was not statistically significant (P>0.05), indicating that despite the slight numerical difference in shell thickness of the two groups (Hatched, Not Hatched), it was not enough to invoke a statistical significance probably due to unequal subclass numbers in the two groups.

Keywords: Hatchability, Quail, Egg Shell