Increasing hatchability of turkey eggs by matching incubator humidity to shell conductance of individual eggs.

One of the most important factors determining hatchability of avian eggs is the proper water balance of the eggs during incubation. In turkey eggs, a total diffusive water loss (F) of 12 +/- 1% SD initial egg mass in 28 days, yielded maximal hatchability irrespective of the combination of eggshell water vapor conductance (G) and incubator humidity (PI), which brought about this water loss. A good correlation was found between G as obtained at the beginning of incubation and the final F in a given PI. The G in a random sample of 1256 fresh turkey eggs was normally distributed around the mean of 18.70 +/- 2.87 SD milligrams (100 g X day X torr)-1 (Coefficient of variation = 15.3%). The distribution of G in eggs with dead in the shell embryos had, in addition, two more peaks of G values [around 22.5 and 13.0 mg (100 g X day X torr)-1]. When eggs were sorted into low (less than 17), medium (17 to 20), and high (greater than 20) G categories, and incubated at low (19.4), medium (26.6), and high (33.9) torr PI, respectively, hatchability increased by a factor of 1.08. Poor hatchabilities were obtained in mismatching humidities and conductances. It seems that hatchability success may be experimentally improved if a correct rate of water loss is fitted to sorted eggs during incubation.