1.initially mating ability reciprocally. 2. Fertility and hatchability percentage. 3. Post hatch brooding: growth, liveabiliy, morbidity, feed consumption and disease susceptibility during life time. 4.productive and reproductive performance later
The strength of the hybrid plays positively with the appearance of the desired traits, and the ill-advised mixing of some hybrids shows some undesirable traits that affect the productivity of birds.
You must first identify the unwanted genes. And then the state of their dominance or ressesive , in which case it is possible to predict the unfavorable results at the mating crosses through the molecular genome.