maddie,
Petsmart does NOT sell the best brands of food. The best brands are Oxbow and Kleenmamas. I heve never seen a food at Petsmart that even makes the top 3.
You guinea pig was likely choking because it's food had seeds in it. A responsible store wouldn't feed guinea pig a food they A. can't digest well and B. can die from.
There is nothing good about the store. And us saying so is not an attack on you, but on the store. So please, just hear us out and stop being do defensive. There is a website made by the owner of this board that explains why pet stores are bad. Please check it out.
http://www.cavyspirit.com/petstores.htm