RE: Will they be able to stay in the same field?
I have Stallions, mares, geldings, colts, fillys, yearlings and young foals, i have many horses, and all horses are different so they may not fight as i have 3 massive fields and ovbiously have a mixture of them in the fields none fight, but we have had fights in the past with some other horses, i just put them with other horses and their fine. Try putting you two horses in seperate paddocks, but try get the two paddocks next to each other so they can pop their heads other the fence and see each other, there may be a bit of squealing, but dont worry. Then after a few months put them together and keep an eye out, bung down some food and see how it goes first there might be more squealing but if it gets to rough go back to how it was (the two paddocks next to each other, also you could bring them both in and groom them and tie them a couple of metres away from each other so they can hopefully And try bonding, but yet again if it starts getting stupid, keep them away. The may be fine together and just have a run around.