Why is my female cat aggressive in a multi-cat home and wants out?

Unfortunately the new cat is likely causing stress and this is a common feeling reaction to stress. She may not want to go outside as long as that other cat is around. It may be difficult to keep the other cat out of your area unless you want to purchase or build a fence. There are fences available that have curvature to the top that make it difficult for a cat to climb over. There are some things you can do at home that can help to manage her stress. Set aside 30 minutes a day for a vigorous play. Use a pheromone diffuser. There is a special prescription food made by Royal Canin called calm which may help. Use food puzzles. Give environmental enrichment. Lastly, your veterinarian has medications which can help as well. Many cats require a combination of therapies. Best of luck.

She probably wants to go outside and has had a change in attitude because she is becoming sexually mature. If you are not planning on breeding her then she should be spayed (sterilized). This will probably stop all these unwanted behaviors.

It sounds like Snowy may need to see a veterinarian to determine if she needs behavior modification medication if she is stressed out by the other cats. She may also benefit from calming treats or products such as Feliway.

Aggression in cats can sometimes be due to an underlying medical cause such as hyperthyroidism that can be treated by your veterinarian. Unusual aggression can also result from increased stress from a change in routine e.g. a move, a new animal or baby in the house etc. If this is the case, your veterinarian can prescribe anti-anxiety medications to get Maria through this stressful time.

Oh my, that's a lot of cats, especially for a household that started with a cat who wanted to be an only cat. It sounds like cat E also would prefer to be an only cat. I would immediately separate E from both A and the B C D group. You have yourself 3 different fractions here and each needs their own space. I wish I could give you an answer that is more pleasing to hear. It's theoretically possible that cat E has some medical problem instead, but from your description, it very much sounds like a personality/behavior issue. The majority of cats would be stressed by this arrangement, unless you have happen to live in a very large mansion so they can spread out. It's just hard to integrate new cats in to households. Wishing you the very best of luck.

This is the time of year when cats start to come into heat again, and if she isn't spayed and there is an intact male nearby, she may be going into heat and trying to push away her previous litter in order to make room for a new one. If you do not wish to have more kittens, I highly recommend having Chloe (and the kittens) spayed if the male cannot be. 5 cats (plus the others you mentioned) is also a lot of cats, and the sheer number may be very stressful for her. Finding homes for the kittens, or making sure everyone has access to their own food, water, bedding, litter, etc can help decrease tension.

Something is probably going on with her, she is possibly ill or in pain and that may be causing her to be aggressive. i would recommend taking her to the vet for a checkup and blood test to make sure she is in good health first.