Izzie - the kickboxer

I just don't know what to say. The rescue group had to leave the property as it was being auctioned and found another property that is much smaller (25 acres - the first property was 80 acres). At the previous property Izzie was in a very large paddock with her friend Possum, Maggie and another horse, Tia. Izzie and Tia hated each other so there were occasional dust ups but plenty of room to get away from each other.  She hated Dodger when he was alive and quite often kicked the heck out of him (poor bugger was blind so couldn't see it coming). At the new property, she is in a very small paddock with Possum and Maggie. However, one of the ponies who lived with the herd is also with them (Possum's mum, Millie). Well, was there a ruckus in the paddock today. I had taken Izzie for a walk and was returning her to the paddock when Millie strolled over. Millie is a biter so she is biting Izzie on the bum and Izzie is kicking the heck out of Millie. It went on and on and on.  I had to rescue a volunteer who was in the paddock at the time as those hooves of Izzie's fly everywhere.  When I left the girls were close to each other but it was not a comfortable closeness and they were eyeing each other off.  That Izzie sure is a little spitfire.  I am wondering if it is a bit of jealousy or what but I can see that she really doesn't have a lot of social skills when it comes to horses and ponies and is very much a loner.