placenta

Question
Is there any polssibility that mares eat their placenta after giving birth?

Answer
Yes, it give energy to mom after birth and it removes it from area so the smell will not attract predators to the new baby.

Lots of animals do it. Horses are Precocial species so the baby is held longer in mom almost a full year, so when the baby is born it is ready to move and can do most everything other horses can do.

I discuss all of this on my horsemanship page of my web site. I would suggest you read my site and it would answer most of your questions about horses.