My cats hiss at a new outdoor cat after moving. Should I intervene?

It does take time for the existing cat to get used to a new addition to the house, and I recommend introducing them slowly to each other. Take the kitten, and put her in her own room with her own food, water, and litter box. Keep the door closed, and for a few days, feed them both treats on other side of door so they associate each other's smell with a good experience. Then let the other cat in the kitten's room while the kitten is in a cat carrier. They can smell each other, but not be in contact. If either becomes upset or show signs of aggression, remove the second cat from the room, and try again later. Praise them when they interact appropriately. When they are interacting well with each other through the carrier, you can let the kitten out of her room, and see how she interacts with the other cat. Praise them when they interact appropriately, and separate them with any sign of aggression or upset. I would get a cat tree with lots of shelves to give the cats vertical space to get away from each other. I would keep the kitten in her room when you go out until they are comfortable with each other.

As long as Oliver is fully vaccinated, it would be fine to let them interact with supervision. The kitten is likely hissing out of instinct and won't necessarily attack Oliver. Usually the cats work out their differences in their own way, but you should be there in case they start acting aggressively towards each other. If they are starting to swipe at each other, then it would be best to give them a little more time separated before letting them interact again. Below is a link to an article with some good advice for introducing the two. https://www.petcoach.co/article/5-steps-to-introducing-your-cat-to-a-new-feline/ I hope that helps and all is well with Oliver and the new kitten.

It could be Obi is letting the kitten know his boundaries and when he wants him to stop certain behaviors. This is normal, and I would not worry about stopping it. He needs to express his feelings in a safe way, and hissing is fine. Aggression is not, and as long as he's not being aggressive, you don't need to stop it. Best of luck.

Unfortunately it's going to take time. That said, there are a few things you can make sure of to help reduce stress, especially in a four-cat household (which is a lot!). Making sure each cat has their own space where they can eat, drink, play, observe, etc without the other cats bothering them can help reduce territorial disputes over these items. Pheromone collars and plug-ins (Feliway) can also be placed on stressed out individuals, or in shared rooms (since everyone seems to be stressed) to help reduce inter-cat aggression. Making sure to have at least one litter box per cat will also help reduce stress and competition over them, and reduce the chances of accidents elsewhere. Otherwise, continued slow introduction of the cats is best. If anyone starts to get agitated or too excited, removing them to let everyone calm down and settle back in is best. Continued aggression and upset may also need a trainer or veterinary behaviorist's help. That said, if your home is very small, four cats may just be too much for everyone to get comfortable.

This is very normal behavior. Make sure you provide plenty of litter boxes and food and water bowls to decrease the stress and competition of the kittens. Also, you can put some feliway diffusers in their room to help calm them. Feliway is a cat pheromone to help calm them but it doesn’t work on everyone. Give them some time and hopefully they will start to warm up to each other. I hope this helps!

Yes, this would definitely be best. When introducing a new cat to the household, I always recommend setting the newcomer up in his/her own room - something like a spare bedroom or office works very well. Put her litter box, food and water bowls, toys and a cat tree or scratching post, etc. in her room so that she has everything she needs to be comfortable. The cats will sniff each other under the door and gradually get used to one another, but this can take a few weeks in some cases before they're ready for any face-to-face contact. Once they are no longer reacting to each other at all through the door, you can start leaving Jayne's door open a crack so that she can come out if she wants to - just make sure that she can always run back to her room if she gets anxious or worried. Over time, she will start spending more time out of her room as she gets more comfortable. Just let her go at her own pace, and don't rush the process :)

If your cats have spent most of their time outdoors and now are spending time inside together then this change in environment could be causing tensions. If they are still outside all the time then it is possible that a new cat has come into the neighborhood and this has disrupted the social structure of the cats, or potentially one of the cats could be feeling unwell and therefore being more defensive, or they could feel they are having to compete for food/shelter. I would be sure both cats have equal access to food and water (they may need their own separate areas to eat/drink so they don't feel threatened) and litter boxes indoors. When indoors I would recommend the use of the Feliway Multicat diffuser https://www.amazon.com/CEVA-Animal-Health-D89410B-MultiCat/dp/B01AVHPFDS/ref=sr_1_4?ie=UTF8&qid=1503838561&sr=8-4&keywords=feliway+multicat, which is a pheremone product. I would consider an examination by your vet to look for underlying health problems as well.