Hi Willowambs – one of the first questions is what kind (brand) of essential oils is it?
If its Young Living than the quality of the oil is great and is natural and most of them are fine… The biggest problem is a lot of people just use the cheaper ones from Amazon or non high quality ones that are essentially not good both animals and humans.
Here are some that are considered safe for rabbits….
Essential Oils Are Safe for Rabbits?
1. Lavender
2. Lemon
3. Orange
4. Fennel
5. Peppermint
6. Eucalyptus
What Essential Oils Are NOT Safe for Rabbits?
Here is a great link that lists ones; https://www.themiracleofessentialoils.com/unsafe-essential-oils-for-pets/
I am not a vet or a seller of oils, so please do some more research on your own…. but I do use essential oils – young living brand – on a different floor of my house from my bunnies (but its open concept so technically some of the smell could go down the stairs) and have never had any problem.
What I would suggest is – if you are using a good quality oil – is run the diffuser during the day when you are home, in your bedroom with the door closed as it would be when you were sleeping.
Than see how your bunnies react to it. Just like people – how I may react to something is different than how you would react to something. And how my bunnies react to something may be different than yours. You dont want to wake up one morning to find that they had a bad reaction while you were sleeping and couldn’t see it.