
One reason most eggs don’t hatch even under the right conditions is unfertilized eggs. Most farmers believe having a rooster in their poultry means that the eggs laid are wrong, which is false.
Egg formation.
Mating is necessary for an egg to be fertilized. Once the yolk is dropped from the ovary into the infundibulum, it is fertilized by a male present. If the male sperm is not present, fertilization does not take place.
After fertilization, embryo development commences as the yolk travels down the egg canal, receiving white coatings. The egg progresses to the shell gland, which receives membranes and forms the shell. The shell takes approximately 20hr, and the embryo grows to about 4 m in diameter. The egg is then laid.
Unfertilized egg
The unfertilized egg has a little white spot on the yolk (germinal disc), which is only observed after breaking the egg.

Fertilized egg
A fertilized egg has a germinal disk with a slight bull’s eye appearance.
Read Also: Ksh 846,750: Exact amount you need to Raise 500 Layers

The best way to determine if your egg is fertilized is to break it. Candling is another method that involves shining a torch light through the egg and looking.
Conclusion
A low ratio of roosters to layers means a low level of mating, reducing chances of fertilization. Always maintain a good ratio of roosters to layers at least 1:4, increasing the eggs laid to be fertilized (potential for an embryo to grow and develop in the right conditions).