Hatch rate measures how effective your incubation was. Calculating it correctly lets you compare hatches and spot a fertility or incubation problem.
The two rates to know
There's a difference between fertility rate (share of fertile eggs) and hatch rate (share of chicks born). Mixing them up distorts your analysis.
- Fertility rate = (eggs set − clear eggs) ÷ eggs set × 100
- Hatch rate of eggs set = chicks hatched ÷ eggs set × 100
- Hatch rate of fertile eggs = chicks hatched ÷ fertile eggs × 100
A worked example
You set 24 eggs. At candling, 4 are clear (infertile), leaving 20 fertile eggs. In the end, 17 chicks hatch. Fertility = 20 ÷ 24 = 83%. Hatch of set = 17 ÷ 24 = 71%. Hatch of fertile = 17 ÷ 20 = 85%.
What is a good hatch rate?
On fertile eggs, 75 to 90% is considered good for chickens. Shipped eggs often hatch lower (50 to 70%) due to transport. A low rate points to a storage, fertility or incubator-setting issue.
Why hatch rates vary between batches
Fertility depends on the age and condition of your breeders, the season and the male-to-female ratio. Hatchability depends mostly on egg freshness, storage and incubator settings. Tracking your rates batch after batch lets you isolate the cause, because a fertility problem isn't fixed the same way as an incubation problem.
How to improve your hatch rate
Pick clean eggs, neither too big nor too small, laid less than 7 days ago. Store them pointy-end down at 12 to 15 °C, tilting them daily. Calibrate the incubator before setting, keep temperature and humidity stable, and respect lockdown. Log every batch to measure your progress over time.