I just moved into a house where the gentleman has two outdoor barn cats. The cats usually come in a few hours a day as they please. They are both fixed males. I have two fixed female cats, very pleasant and kind. One is very shy and skittish. When I was not home, the man let the male cats into the house where they proceeded to chase and fight with my cats. We decided to bring a large dog crate into the house, and take turns putting the respective pairs in there. The cats were all relaxed and fine. I was planning on doing this for a few weeks and just letting them grow accustomed to each other. Last night the guy let his cat out when he went to bed and I came home to find my cat cornered in her litter box and the male growling. I grabbed him and right as I went to he attacked her. She got a little scratch on her arm and it bled a bit, but she appears fine. Is it possible barn cats just can't be socialized with indoor cats? The gentleman is leaving in a few days and I don't know how best to continue getting them used to each other. I am probably going to find a new place to live when he returns as I don't want to risk my kitties health. Thanks for reading!