Two New Kittens

Good Morning All,

My boyfriend and I recently brought home two new kittens that are 12 weeks. They were in the same crate at the shelter so we thought that after they were both fixed they would be ok when we reintroduced them in the house. The male kitten is very wild and loves to play. He isn’t being aggressive with her by hissing or growling he is just trying to figure her out. The female on the other hand is very standoffish with everyone. She will let you pet her and she will purr but when it comes to the male she keeps hissing at him and growling. She was fixed this past Monday and we brought her home on Tuesday. We brought the male home Sunday and brought him back to get fixed Tuesday. We did have them separated for a few days because she wouldn’t come out from under the bed, but then she wanted to go out and explore. Yesterday and today she has been kind of playing but still being aggressive with the boy. Is it still just getting use to the environment or should I be worried. I feel like she is starting to stress out the male kitten. He follows her around the house and won’t still still anytime she moves. Any advice to make this transition for them easier is appreciated!