horse to horse aggression

Question
I have recently purchased a 15yr old mare who is pregnant. She shares a pasture with two other mares with foals and one gelding who is about 8yrs old, the problem is not with the mares being aggressive towards her but the gelding. Blaze (our mare) is not aggressive but Trigger (the gelding) has let her have it on more than one occasion , just today we went to check on her and found her soaked in sweat and she has multiple bite wounds some of them open sores, we have since separated the gelding from her, but we cannot keep them apart always, how do we fix this and why does he single her out for his whipping boy.?

Answer
Hello Monica,

You will have to separate them.  It is the nature of this herd animal to have a pecking order.  She is low in the order and she will be picked on endlessly until you protect her.

The gelding is bullying her because he is probably lower on the pecking order than the other mares.  Unless you want more bites and kicks for who knows how long, you will have to separate him from the mares, or her from him.

Best wishes,
Dorothy