There is both a PetsMart and PetCo here. Both seem about the same in cleanliness, I've never noticed them to seem dirty. PetCo's birds and fish look better than the PetsMart here. PetCo's prices used to seem higher than PetsMart but within the last couple years, seem very comparitive.

I end up shopping at PetCo the majority of the time because PetsMart doesn't offer the food I get for my dogs (Royal Canin Natural Blend). I've never seen any animals that were injured, dead or looked to be dying at the PetCo here. I have occasionally seen a few dead fish at PetSmart, and their birds don't always look as healthy or well kept as PetCo's.

I believe it solely depends on the management of each store.