Do birds ever fly around inside the store.

Sometime they do. They have to build their homes too

That's the weirdest possible question.

Birds of a feather flock together... Don't ask why ! !

Yes they do. Whenever they can gain access to a large structure they generally get in and fly around. Consider it from the birds Point Of View. Outside with just sticks to make a nest for the young ones or inside a big box store with all new modern building materials to make use of. It seems obvious what the choice will be. Not to mention the advantages during inclement weather.

Yep....at Home Depot, too.