I have 4 lovely little ladies all together. 2 of them are 4 years old and have recently fallen ill with respitory infections. In the last couple days they have both fallen a full story resulting in potential injuries for my old old ladies. I am not willing to let them get hurt any longer so I am needing to seek advice from all of you and ask what the best solution would be for the meantime as they continue to age? For now I have put all four of them in a smaller one story cage so that they cannot get hurt. It is a bit crowded in there though so I don't feel the best about this plan. I also don't want to seperate them as they are all best buddies and sleep and snuggle together. They get confused when seperate. I don't think that is what they need at this time either. Internal moral dilemma here. Thanks in advance for any advice at all, it all helps one way or another.

TLDR ; 2 old rats keep getting hurt in current cage due to falls. Don't want to seperate them from 2 younger sisters. One story cage too small for all 4.