While I too hate to see any animal suffer by buying the animal you are NOT helping the situation. Petco/Petsmart/Petland and the rest won't get the message about proper care until that message comes via lost sales. Once they figure out that people won't buy distressed ,sick or poorly taken care of animals then they will make changes for the better.

So send the right message that you won't support their store till they take care of their animals.