I would think it would depend on where they got the chicks (are they from healthy, hardy stock and in what conditions does the breeder keep his stock) and how the individual store cares for them.
If you get animals from them, I would HIGHLY advise quarantine, however, because you don't know what they have been exposed to (even just from customers in and out of the store) and what they may be harboring. I found that out the hard way. In my case, it was with rabbits, but I ended up bringing home pasteurella and had to destroy my entire herd, sanitize, and start over. Heartbreaking.
I am not saying any of this was TSCs fault. The rabbits all appeared healthy when I bought them. But they had obviously been exposed (I have never previously had ANY disease problems) and all the stress involved with transport to the store, strange people constantly milling about, and then being moved to my place was obviously too much for them and they succumbed to the illness.
I don't think it is a good idea to get animals from places like
TSC because, as mentioned above, you really don't know where they came from and the whole situation is just too stressful them.