5 days old is much too young and fragile. They probably came from what is akin to a puppy mill. Most private breeders will wait until the babies are 6 weeks old to ensure they are stable, eating well and thriving.
Babies that small have specific needs, unless the pet shop is aware, they will lose them too.
I've seen pet stores set out a plate of whole/mixed frozen veggies, with green beans almost as large as the babies and expect them to eat it. Even worse, adult sized crickets or mealworms and no basking area.
I wouldn't buy a beardie from a pet store unless I knew that the owner's care of his animals was exceptional, and that owner would not have 5 day old beardies in the first place.
Another common problem is that enclosures are not properly disinfected from species to species. The previous animal in that enclosure may have had parasites or some other disease that is passed along to the new hatchlings.
You also will be paying top dollar, paying the breeder and the stores mark-up. Plus, anyone can call the beardies red in a pet store, telling you they will develop color later and they may never...
Buy online from a reputable breeder, ask for specific pics, ask to see pics of the parents. Save yourelf some heartache.
TheClassyLizard