Helping cats adjust to a new home

Hi everyone, I'm in a bit of a panic mode right now. My friend Kristen is moving to an apartment next month and she has two cats, Milo who is this hyper 3-year-old orange tabby and Lucy who is a very shy 2-year-old DSH. The twist is that the apartment already has a resident cat. She is debating whether to ship them separately to different locations or bring them all in at once and let them figure it out. I know that sounds crazy but she is stressed out. What actually helps cats adjust to a new living environment quickly? I feel like if I can help her with this, I can stop worrying about my own move which is coming up soon too.

Shipping them separately is a logistical nightmare and usually results in higher stress cortisol levels. I recommend a phased introduction. For the resident cat dynamic, look at Introducing Rio to Willow. That thread has a 14-day timeline that worked for my cats. For the new cats' adjustment to the space itself, vertical territory is key. See Maximizing vertical space for how to set up a 400 sq ft apartment. If you are worried about the move day itself, Flying with my cats covers carrier prep, though I assume Kristen is driving.

Oh wow, that sounds intense! I remember when my siamese moved and she just screamed for three days straight. It was so funny but also sad. I think the shy one, Lucy, will need the most help. Did you guys try the scent swapping thing before they even see each other? I read somewhere that it helps a lot. Also, pheromones? I use them all the time but I am not sure if they actually do anything or if it is just a placebo for the owners.

Scent swapping is non-negotiable for a shy cat. I have a protocol for this in Scent swapping routine. It involves using a soft cloth to rub the cheeks of the resident cat and then placing it near the new cats' food bowls. As for pheromones, I ran a control test on my two cats last year. The diffuser reduced hiding time by 15% on average, but it did not stop the initial aggression. It is a mild aid, not a solution.

Wait, so you are saying the diffuser isn't a magic fix? I bought two of them because I was so scared my calm cat, Mia, would get stressed out. She is 4 and usually very chill, but I read that even calm cats can get triggered by new smells. I am just so worried that if I do this wrong, the resident cat will attack Lucy. I need to know if there is a specific order to things. Should I worry about the resident cat's age too? I saw a thread about older cats but I am not sure if that applies here.

The age of the resident cat matters a lot? I am asking because my Bella is 6 and has asthma. When we moved last year, the stress made her breathing really bad. I had to use a nebulizer for two weeks. If Kristen's resident cat is older or has health issues, the stress of a new cat could be dangerous. I would look at Moving my 6 year old Bella to see how I managed that. It was a total mess. Also, if the new cats have any health issues, like fleas, that changes everything. I had to treat my Charlie for fleas right after moving and it was so hard to keep them separated.

Health issues change the isolation period. If any cat has parasites, you must treat them before introduction. See Managing fleas during a move for the timing. If the resident cat is healthy and young, the standard protocol in Introducing Rio to Willow applies. If the resident cat is older or has respiratory issues like paulr18's cat, you need to extend the separation to at least 21 days and use air filtration. The answer depends on the specific health status of all three cats.