When do I stop turning grouse eggs?

After day 22, according to Mississippi State's incubation table. From then on leave the eggs still, raise the humidity, and keep the incubator closed so the chicks can get into position.

What temperature and humidity do grouse eggs need?

Mississippi State lists 100°F in a forced-air incubator (2 to 3 degrees more in a still-air one). Humidity is a wet-bulb reading of 83 to 87°F until day 22, which works out to about 49 to 59 percent relative humidity, then 90°F wet bulb (about 68 percent) for the hatch.

When should I candle grouse eggs?

Around day 8 and day 16. Those are the chicken candling days scaled to a 25-day hatch (about one-third and two-thirds of the way through), because the extension tables only list candling days for chickens.

Free tool

Grouse egg incubation calculator

Grouse eggs hatch in 25 days. Enter the day you set them and get the whole hatch on a timeline, with the incubator settings and the source behind every number.

Date eggs were set

Both tables that list grouse say 25 days.

0
Set eggsTue, October 6, 2026
Eggs go in the incubator. Begin turning (or confirm the auto-turner is on).
8
First candlingWed, October 14, 2026
Look for spider-web veining. Remove clears and early quitters.
16
Second candlingThu, October 22, 2026
Embryos should fill most of the egg with a clear air cell. Remove any quitters.
22
LockdownWed, October 28, 2026
Stop turning, raise humidity, and keep the incubator closed until hatch.
25
Hatch daySat, October 31, 2026
Pips and zips! Leave the chicks in until fluffy and dry, up to 24 hours.

Downloads a .ics file that works with Apple, Google, and Outlook calendars.

How long do grouse eggs take to hatch?

25 days, and for once the references agree. Here is what each one prints.

Source	Days to hatch	Applies to
Mississippi State University Extension	25	Grouse
University of Kentucky Cooperative Extension	25	Grouse

Incubator settings for grouse eggs

Temperature: 100°F forced-air (add 2–3°F in a still-air incubator)
Humidity to day 22: about 49–59% (wet bulb 83–87°F)
Humidity for the hatch: about 68% (wet bulb 90°F)
Stop turning: after day 22
Open the vents further: day 21

These come from Mississippi State's incubation table, which gives humidity as a wet-bulb temperature. We converted it to relative humidity with the same extension chart, so treat the percentages as close, not exact. Follow your incubator's manual where it differs.

Hatching something else?

Common questions

How long do grouse eggs take to hatch?: Grouse eggs hatch in 25 days. Every reference we checked (Mississippi State and Univ. of Kentucky) gives the same number. A day early or late is still normal: warm incubators run fast and cool ones run slow.
When do I stop turning grouse eggs?: After day 22, according to Mississippi State's incubation table. From then on leave the eggs still, raise the humidity, and keep the incubator closed so the chicks can get into position.
What temperature and humidity do grouse eggs need?: Mississippi State lists 100°F in a forced-air incubator (2 to 3 degrees more in a still-air one). Humidity is a wet-bulb reading of 83 to 87°F until day 22, which works out to about 49 to 59 percent relative humidity, then 90°F wet bulb (about 68 percent) for the hatch.
When should I candle grouse eggs?: Around day 8 and day 16. Those are the chicken candling days scaled to a 25-day hatch (about one-third and two-thirds of the way through), because the extension tables only list candling days for chickens.

Where these numbers come from

Important Incubation Factors. Mississippi State University Extension.
Development of the Chick (ASC-195). Tony Pescatore and Jacquie Jacob, University of Kentucky Cooperative Extension. December 2012.
Care and Incubation of Hatching Eggs. Dr. Tom W. Smith, Mississippi State University, Poultry Science.

We read each document ourselves and last checked this page against them on October 5, 2026. Where they disagree, we show you the disagreement instead of picking a winner quietly.

Get a nudge on lockdown day

Log the hatch in PoultryPal and it counts down with you, then records how many chicks hatched and your hatch rate. Premium adds lockdown and hatch-day reminders. Free to download on iOS and Android.