I worked for Petco. It's the store policy that unless you're going to buy it (ferret, gerbil, etc) we won't take the pet out. Why?? Because alot of people like to use Petco as a "petting zoo". If we took out animals for anyone that came into the store, we'd be busy all the time, accommodating customers. Besides, animals being handled by customers is a liability for the store should one bite them. And, germs can make the animals sick. Don't be angry. It's not just you.

Parakeets could easily slip out of your hands. Another reason why they wouldn't take one out. That and the fact that they're very difficult to catch just so someone could pet it.