We have a big group of mice we call the Nuts, the group contains females and neutered males and all but one of the mice are almost definetly closely related. Cancer has hit and a few in the group have lumps, deaths mean the group has decreased in numbers in the time since we put them in their current big cage and severe resp issues in the past have led to some of the mice aging quite early. Altogether over 2/3 of the group aren't in the best of health anymore, they're all happy and still clearly enjoying life but at the moment its basically a big group in a huge cage with a lot of the mice being affected by health issues to some degree or another.
We've seen in the past that sometimes when an animal has untreatable health issues, moving them to a smaller cage can help a bit. It seems to give them less territory to patrol and keep an eye on and it also makes absolutely sure that everything they need is close by. Given the condition most of the Nuts are in now, we feel they may benefit from moving to a smaller cage but the past resp issues complicate things a bit...
The resp issues have affected the group more than once in the past, we have reason to suspect the issues are caused by myco and that they may return in future. Stress may increase the risk of it returning. If it returns now then we are 99% sure one mouse won't survive it and are 75% sure quite a few others won't either. Moving the mice to a smaller cage - even with the same substrate, toys e.t.c may cause them stress. In the past they have taken cage changes quite well but we never figured out why the resp issues have flared up before, we just know it wasn't when mice moved cages.
Despite the risks we do think the group would probably benefit from moving to a smaller cage we have spare. (By smaller I mean 100cm Barney, their current cage is the Elegance with a full shelf in it, they wouldn't be going to a small cage but it would be quite a bit smaller.) The worry is that if we move them and it stresses anyone into resp symptoms we will probably lose the majority of the group in a matter of days. We do have more of the medication that eventually cleared the resp issues before but we'd probably need to speak to the vet who prescribed it before to be sure we got the dose right as we've lost quite a few of the group since the medication was originally prescribed.
In short... We think our big group of mice would benefit from downsizing. If we downsize them and it causes their past resp issues to recur again most of the group won't survive it.
Opinions/advice would help a lot.
I know most probably won't have experience to help with advice, but even if you could think it through and see what you think... Any/all comments/advice about if we should downsize them or not or if you think the risks are worth it e.t.c would be appreciated at the moment.
Currently one of two pet-humans of some hamsters (syrian, roborovski, chinese and russian hybrid), mice, mongolian gerbils and a duprasi :)