There are a lot of people talking about guinea pigs being housed in 2 tier hutches. Has anybody had problems with pigs hurting their backs in these. One of our pigs hurt her back jumping out of my hands into the run (she was a baby with severe inbreeding- her dad was her half brother, and her uncle was her grandad, 2 siblings were born with microthalmia, one of whom died at about 3 months old) so I thought it was possibly a problem with that. I now know of another pig who hurt its back using a ramp in its cage, it was also a young pig. Is it a common problem in young pigs.