Guinea pig sleeping behaviour

[PhoebeH123]

Hi,
I have 6 female guinea pigs. My hutch consists of one large sleeping area where they’ve all happily slept together. But for the last week or so now the 2 older guinea pigs will not sleep upstairs. Any ideas why they won’t sleep with the others? I’ve not seen any dominant behaviours myself. Thanks

 

[GuineaPigLover7891]

How old are the older piggies? Is there any chance that they are having trouble climbing the ramp?

 

[Siikibam]

They may just not want to sleep upstairs now, and want their own space. How big is the hutch and how big is the sleeping area?