- Cow — about 283 days.
- Ewe — about 147 days (roughly five months).
- Nanny goat — about 150 days.
- Sow — about 114 days (three months, three weeks and three days).
- Mare — about 340 days, and very variable.
- Chicken eggs — 21 days to hatch; duck 28 (Muscovy about 35); goose about 30; turkey 28; quail about 17.
These are averages — breed, litter size and conditions all move the date. Use the gestation calendar to work out your own dates and talk to your vet about anything that looks late.