donkey spontaneous abortion

Question
I recently rescued/adopted a pair of mini donkeys to keep the coyotes from eating my sheep. Works good. The donkeys are intact male and a female, so I immediately separated them. Past owner said the she may be bred, and this morning she was standing over a premie (no hair yet) fetus and placenta. She seems okay, but I would like to know why she aborted. Would this happen if the parents are related? Past owner said they weren't...but I'm not-so-confident about the history...What other things could cause her to lose the foal? Fetus looked normal, just really premie.I think this jenny has had stillborn foals before, but the past owners said that the jack killed the baby....now I wonder...I do not know the ages for sure, but a very amature look at the teeth would seem to indicate that she is not 20 yet.

Answer
Hi- sorry about the wait-internet crashed on me- As to your question- there are many reasons that she could have aborted-was she underweight or malnourished?? Also your theory on the pair being kin to each other could also be true. If she has had premies before- id say that there is something that is keeping her from carrying them full term internally.Do you have any idea if the intact male was the sire to those also???. Sorry I can't be of more help-Good luck with them!