How would one calculate fertilization and hatch rate?
In the commercial hatcheries they typically have two separate operations. One group provides hatching eggs. The second group hatches them. Each group is interested in different things.
Fertility is not the only reason eggs are unhatchable though it is a big reason. Sometimes the hens don't lay a good egg or something about the way the eggs are handled makes them unhatchable. Their performance is based on them providing hatchable eggs.
The people that hatch the eggs don't care about that. Their interest is only in hatching the hatchable eggs. So they are measuring different things. One group is measuring hjatchability, the other hatch rate of the hatchable eggs.
A poultry science professor that acts as a consultant to commercial operators and actually opens some of the unhatched eggs (or teaches other to) to determine what went wrong said each group is typically responsible for 5% of the unhatched eggs. They typically get about an overall 90% hatch rate. He also said that if the egg starts to develop but stops in the first week of incubation it is often due to something that happened before the egg was incubated. If it dies in the last week it is generally to do with the incubation. I'm not sure that applies to us since we don't all manage our incubators as rigidly as the commercial operations do.
I'm different. I both provide the hatching eggs and hatch them. To me my hatch rate is eggs in and chicks out. But I don't set really dirty eggs, fart eggs, cracked eggs, soft shelled eggs, or double yolked eggs.
Set 30 eggs:
15 Polish
11 mix
4 Showgirl
2 duds and 2 early quitters removed at day 7-10 (all polish)
Hatch:
11 polish
10 mix
2 showgirl
I don't know why those two early quitters quit so I'll make the assumption they were unhatchable to start with. So that would mean your hatchability rate is 26 out of 30 so 87%. Your hatch rate of hatchable eggs would be 23 out of 26 so 88%. But the way I calculate mine it is 23 chicks out of 30 eggs in so 77% which is pretty close to my average.
When someone on here mentions they get a really good hatch rate, read it with a grain of salt. You never know what they are actually measuring. I remember someone on here measured hatch rate to be the eggs that hatched compared to the eggs that were alive at candling to go into lockdown. They had a very high hatch rate.
