Is there any way you can wipe the older cat with a towel and the kittens with a different towel and then switch? You could even put the kittens' towel under the food dishes of the older cat for a few days to create a positive association before bringing them in.
Similarly you could allow the kittens in the yurt while the older cat is outside for a half hour or hour several times over the next few days instead of several days. Scent is such a huge part of pet interactions, that the more scent exchange and positive exposures you can do, the better!
I love Feliway/Comfort Zone for Cats for stressful settings (I mentioned it in another thread for a similar moving issue lol), and they do have a spray version, not just a diffuser that needs to be plugged in 24/7. That might be worth a try as well.
Are there any spots you could set up for your older cat that the kittens won't be able to reach? Maybe something up higher than they can climb?
Similarly you could allow the kittens in the yurt while the older cat is outside for a half hour or hour several times over the next few days instead of several days. Scent is such a huge part of pet interactions, that the more scent exchange and positive exposures you can do, the better!
I love Feliway/Comfort Zone for Cats for stressful settings (I mentioned it in another thread for a similar moving issue lol), and they do have a spray version, not just a diffuser that needs to be plugged in 24/7. That might be worth a try as well.
Are there any spots you could set up for your older cat that the kittens won't be able to reach? Maybe something up higher than they can climb?