new horse getting hurt

Question
I have two mares one who is 4 and the other is 16.  The oldest one is extremely dominant, very strong caracter.  One of our friend has recently ask if we could keep his horse and she is an 18 year old mare and we agreed.  We are having alot of problems both of my horses 4 and 16 year old seem to gang up on the other horse alot, they run after her, and it seems that everyday they've hurt her in a new spot so she can get better because they keep hurting her.  I know that my 16 year old with the strong caracter tends to start up alot of the fights or running around but what can we do to stop it before my friends horse gets so badly hurt that she can't pull through, especially at 18.  Should we ask our friend to board his horse elsewhere??

Answer
hi Nathalie,
usually it takes a few weeks for the horses to figure out the new peckinh order when a new horse comes in. if she has not recieved any serious injuries such as a bad cut, swollen leg, or any bad kicks, keep her in there and they will be ok. every horse has its place in the line. when a new horse comes in that line has to be re ordered. if they continue to beat her up badly i would suggest you just separate her from them. making a side pen would be a good idea. but keep it close to the other horses so she feels safe and part of the herd. good luck
amanda groff