I have adopted an ex-feral who was tame with me but rather agressive to the other ferals in the group. She has been spayed and has lived in the house with my four other cats for 3 months. She has adapted to home life perfectly except for the fact that she gets very manic (especially at night) and chases two of my other cats (both neutered males who are the oldest of the bunch). One of them is especially nervous and dominated by the others and is chased by her incessantly. He has now taken to hiding outside and its worrying me that he might one day run away completely. I just spent 10 days away and put the new female in a cat shelter to protect the others whilst I was gone. Now she is back and I have separated her as much as possible from the others (especially the nervous male). Any suggestions would be gratefully appreciated. By the way, the others (three males and one female -all spayed/neutered live together peacefully.