For your horses, 3 days. Your horse ages every two months unless it has the Water of Youth, which in the case your horse would age 1 month each time instead of 2.
12 months, (6 real-time days).
In 12 Howrse months. You can wait 6 days, or you can use 6 aging points if you have it.
20 months
It is 12 months.
2 years 6 months
Press the "info" button (Magnifying Glass) on your "Reproduction" tab and it should say "Gestation: 8 months, 6 months, etc...
Your horse can be in gestation 12 months.
12 horse months. Equal to 6 days
On Howrse, a horse can board at the age of 6 months.
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Gestation lasts 12 months on Howrse, but it all depends in real life if you use aging points. PM me! I am chey19 on howrse
When you have a mare which is 2 years and 6 months old, you can breed her, and get a foal.