Oh dear! I've had that happen before on storage units but never a cage. I bet that was interesting to try and manoeuvre with a wheel missing!Blooming wheels fell off the Rainforest Georgia cages! One came off Pips and 2 off Glossops, what a struggle that was for hubby to get them back on. Never had that problem with our old cages, typical isn't it. The Bolivia cages were okay thankfully.