The RSPCA animal home at West Hatch in Somerset is struggling to cope with a glut of guinea pigs.
The centre currently has 25 heavily pregnant guinea pigs
The centre near Taunton is caring for 77 of the creatures, 25 of which are heavily pregnant.
The guinea pigs have over-spilt into the aviary and rabbit enclosures, which are now full.
Care Assistant Karen Reed who is in charge of the guinea pigs said: "We urgently need to find new homes for the ones we have before the babies arrive."
The centre has a list of guinea pigs waiting to come into the shelter from owners who can no longer care for them.
Miss Reed said finding new homes for the guinea pigs and other small animals was a constant problem.
"People do not associate them with the RSPCA animal homes in the same way they do with cats or dogs," she said.