I received a 1.5 y/o spayed female into my house of 2 older neutered males (no alpha) and one 1y/o spayed female. I have never had any problems with any of my cats adjusting to each other. The two older males are mellow and don't care too much about the new addition. I usually give the cats a max. of 2 months to finally be comfortable around each other. I have had the new female for about 8 months now and she still growls and hisses at my other cats. Even when they just lay there and watch her walk by. They very rarely to never attack her. She is a very lovable cat and has never tried to scratch me or my other cats. She just growls and runs away from them when they get too close. Is this a problem? Should I find her a home with no competition?