When I bought my mare she had a 3 month old filly at her side that didn't come with her. I'm sure I could have bought her, but I wasn't really prepared for a foal and the foal wasn't included in the asking price of the mare.
So we hauled momma off and left baby behind. It really broke my heart, but I thought my family would kill me if I bought home a mare AND foal. I was pushing my luck buying the mare.
The guy assured me the foal was old enough to wean and wasn't worried about it at all.
Anyway, I talked to the guy I bought the mare from about a year later and he said the foal got sick and almost died. Eventually she pulled through and they sold her to someone. I don't know WHY the foal got sick, but I feel it was a result of me taking her mother away because she was fine when I went and looked at them. So that made me feel like crud! I wish he would have called me- I would have went back for the baby.
Anyway, that's neither here not there. But I would never want to wean one that young after that experience.
The mare I bought ended up being pregnant and I ended up with a foal anyway! That's them in my avatar.
I ended up weaning him at 7 months. Now they are back together because she keeps him in line.