One of the reasons guinea pigs should be kept in (at least) a pair, is that if one of them sleeps, the other keeps the watch over him/her. Just to inform you.
Normally thay get into a routine when there's 2 or more as ones there own thay get hi anxiety which doesn't do them any good.& Thay sleep with there eyes open alot of the time.plent food & grass normally works.
Funny you said that I had 2 that lived under my bed I had to make decking I could pull out to make there bedding and clean them up.im surprised thay are suffering with insomnia stuff them with grass and get them in a run outside and get them into a routine,iv been rescuing guinipigs for over 20 years and routine is very important them nice clean bedding for bedtime, where there's a bit of heat and thay sleep well, guinipigs are sort of nocturnal thay nap every few hours plenty hay and wet food dose the trick,but also lots of cleaning up.Thay suffer depression and anxiety very easily, which can upset them sleeping with can be difficult to tell with Different people.
