TSC and feedstores have chicks in the spring. THEY order bunches of them which will keep them warm during shipping. THEY suffer any shipping/stress losses.
YOU can buy just a few chicks from them, sometimes they have a minimum of 6 to avoid those "Easter present" type purchases, but it's fewer than you can usually have shipped. Usually you can get sexed pullets or a sexlinked breed to make sure you get (mostly) hens.
TSC uses big stock tanks for brooding them, and people mix the chicks up, but if you ask when they are coming you can get there early before they are too mixed up.
Our other feed store has a real "chick brooder" thingy, with separate levels for different breeds, so there isn't too much mixing up. If the tag says Barred Rock pullets, that's probably what you will get.
I know
TSC gets "pullets" which are usually White Leghorns, also they get Red Sexlinks BUT they often sell them mixed in with other Production Reds so you have to know which color to buy to get girls (the employees won't know). The other feed store gets theirs from Ideal and all hatchery-sexed as pullets.
If you buy from an individual, you are rolling the dice and will probably get "straight run" with as many roos as girls. I have gotten lucky and found someone local who had sexlink chicks, but even he didn't know what he had! LOL