Egg Incubator Calculator

Standard incubation periods by species

Incubation times are remarkably consistent within a species. These are the published averages from poultry extension services at Mississippi State, University of Georgia, and incubator manufacturer data:

• Chicken: 21 days
• Coturnix quail: 17-18 days
• Bobwhite quail: 23-24 days
• Mallard / Pekin duck: 28 days
• Muscovy duck: 35-37 days (the longest of common poultry)
• Turkey: 28 days
• Goose: 28-32 days (varies by breed)
• Guinea fowl: 26-28 days
• Peafowl: 28 days
• Pheasant: 23-25 days

Temperature and humidity targets

Temperature is the single most important incubation variable. Too hot and embryos die. Too cold and development slows or stops. The standard for all common poultry species:

• Forced-air (fan) incubator: 99.5F (37.5C) measured at egg-top level
• Still-air (no fan) incubator: 101-102F (38.3-38.9C) measured at the top of the eggs, because heat rises and the air above the eggs is always warmer than the air below

Humidity varies by species and by stage:

• Chickens, quail, turkey, guinea, pheasant, peafowl: 45-55% days 1 through lockdown, then 65-75% during lockdown
• Ducks and geese: 55-65% early, then 75-85% during lockdown (waterfowl need much higher humidity)

Candling: when and what to look for

Candling means shining a bright light through the egg to see what's inside. Do it in a dark room with a bright LED candler. Typical schedule:

• Day 7 (chicken), day 5 (quail): Look for a visible embryo with blood vessels radiating from a central dark spot. Clear eggs are infertile. Blood rings indicate early quitters (embryo died). Remove any clear or quit eggs.
• Day 14 (chicken), day 10-12 (quail): The embryo should fill most of the egg except the air cell at the fat end. You may see movement. Any egg with no clear development should be pulled.
• Day 18 (chicken, lockdown): Stop candling. The embryo should fill the egg with only the air cell visible. From here, do not disturb.

Lockdown: the final 3 days

Lockdown is the crucial final stretch. Three days before the expected hatch:

1. Stop turning the eggs and remove the turner or turning tray
2. Raise humidity to the lockdown target (65-75% for most, 75-85% for waterfowl)
3. Do not open the incubator until all chicks have hatched and dried (24 hours after the first pip)

Opening the incubator during lockdown causes a humidity crash that dries the inner membrane, shrink-wrapping the chick and killing it. If you must open briefly, add warm wet paper towels immediately to recover humidity.

Expected hatch rate

Fertility and hatch rate are two separate numbers:

• Fertility: The percent of eggs that were fertilized. Strong flocks run 85-95% on fresh eggs. Shipped eggs drop to 50-70%.
• Hatch rate: The percent of fertile eggs that actually hatch. Home incubators typically achieve 70-85%. Commercial hatcheries run 90%+.

So if you set 12 chicken eggs at 85% fertility with an 80% hatch rate, expect about 12 x 0.85 x 0.80 = ~8 chicks. This is normal. Plan your setup and brooder space around realistic hatch numbers, not the total egg count.

Common incubation problems

• Eggs hatch early: incubator ran too hot. Chicks are often weak.
• Eggs hatch late (more than 1 day past due): incubator ran too cold. Give an extra day or two before giving up.
• Chicks pip but don't hatch: humidity too low at lockdown (shrink-wrapped), or eggs rotated by malpositioned embryos.
• Sticky chicks: humidity was too high during days 1-18 (insufficient moisture loss, leading to oversized chicks that stick in the shell).
• Lots of clears at day 7: low rooster-to-hen ratio, old breeding flock, or eggs that got too cold before incubation.