How to stop 6-week-old littermate kittens from growling and hissing?

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!

IT can be common for two cats to get along sometimes and not other just like children. The cats are working together to figure out perfect harmony in there environment. I would not be concerned unless you notice abnormal urination/defecation or you feel like the two cats are constantly fighting. IF they are having occasional disagreements that can just be normal pet behavior. If you feel the younger cat has a lot of energy I would recommend trying to increase play by hiding toys and treats around the house. Hope that helps

If only pets could talk! Cats can be very reactive and can also get frustrated easily. It’s possible they saw another cat out the window and are reacting. You may try to separate them for a few hours. Keep the environment calm and check on them frequently to make sure they are not agitated. You want want to close the blinds to block out any views of the other cat. If the behavior continues, have them examined by the veterinarian. I hope this helps and please feel free to post any additional questions.

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.

Unfortunately, kittens that were bottle fed can be aggressive and not as friendly. You can try to put some feliway diffusers in the House and spray her sleeping areas. Feliway is a cat pheromone which can sometimes help to calm them. Also, give her more time. She has been moved from multiple house in her short life and now around new cats (they don’t usually remember family). This can be stressful and can take weeks for them to acclimate to. I hope this helps and she starts to get use to her new living conditions.

I recommend first to have the kittens examined by the vet to make sure they are healthy and free of infections or parasites. If they are healthy, I recommend to start littler box training. Here is a link which may help: https://www.petcoach.co/article/litter-box-training-for-your-kitten/ Similar to crate training a puppy, I recommend to keep the kittens in a small room with their litter box. They can come out for breaks while being supervised but otherwise, they should be in their room. This includes sleeping there since you are having trouble with them urinating on your bed. Also make sure you are using a large, uncovered litter box with a clay-based clumping litter that is easy for the kittens to climb into. The box should be scoped at least twice a day for right now. I hope this helps and please feel free to post any additional questions.

Hello, sorry to hear about your kittens. If mom was away from the kittens, if she had a bath, or if the kittens had a bath then they could be having a hard time recognizing their smells. If this behavior continues then you may need to separate them and reintroduce them slowly. Otherwise, keep an eye on them and make sure that they are not fighting too often. Hope this helps and best of luck.