Effect of egg weight on fertility and hatchability in improved varieties of backyard poultry

The improved backyard variety of chicken produces relatively larger size of eggs compared to commercial layer birds at any point of laying period. The size and weight of egg influence the hatching performance and day old chick weight, which ultimately influence the survivability and future performance of the bird. The eggs weight varies from 45 to 75 gm in Vanaraja and Gramapriya chicken. A study has been conducted to investigate the effect of egg weight on fertility and hatchability in Vanaraja and Gramapriya chicken at particular age. The eggs from birds of 50–52 weeks of age were collected and incubated in three batches. All the eggs were divided in three groups depending on egg weight. The Gr. I include large eggs, weighing >65.0 gm; Gr. II include medium size eggs, weighing >52 to <65 gm, and Gr. III include relatively smaller size eggs of <52.0 gm. The fertility, hatchability, weight loss during incubation and chicks weight were recorded in three batches in 185, 270, 137 numbers of eggs in Gr. I, Gr. II, and Gr. III, respectively in Vanaraja and 177, 270, 210 numbers of eggs in Gr. I, Gr. II, and Gr. III, respectively in Gramapriya. The result revealed that the size of egg had a significant (p<0.01) effect on fertility, hatchability and chick weight. The highest level of fertility was observed in medium size of eggs (92.59±3.19%), followed by large (90.82±4.57%) and small size (83.53±4.54%). The hatchability on TES was found to be higher in medium size eggs (85±7.56%) as compare to small size eggs (76.22±3.79%). For large eggs the weight was negatively correlated with hatchability on TES (p<0.05) and on FES (p<0.10). In medium size eggs, the egg weight was positively correlated with fertility (p<0.01), hatchability on TES (p<0.05), and on FES (p<0.10). In small size eggs, egg weight is negatively correlated with hatchability on FES (p<0.05). Therefore, the study indicated differential hatchability pattern which was highly correlated with egg weight. Hence, selection of medium to relatively higher size of egg would be beneficial for achieving better hatchability and future performance of the chick in improved birds for backyard poultry.