I ordered chickens from My Pet Chicken, but I ended up canceling my order. Customer service was very nice over the phone, but the impression they give you on the site is that you can get the chicks shipped in one or two weeks. But after I placed my order, I was told they didn't have Welsumers after all. I changed my order to Ameraucanas, Faverolles and Speckled Sussex, and they told me my ship date would be in two months, because the Salmon Faverolles would take too long to get. So I changed AGAIN to just Ameraucanas and Sussex, and it was still more than a month.
As I said, I canceled at that point. This process of changing orders took about a week in itself, because they apparently had to check around to see what delivery dates could be with the hatcheries they work with. I decided that I could buy eggs and hatch them faster than I could get chickens from them. And considering that the surcharge for shipping less than 25 chicks is substantial, I was saving money to buy an incubator and hatch my own eggs. Not to mention the fact that I could get what I wanted, and the chicks would be less stressed from not having to go through the mail.
That was my experience. I'll say again that they were really nice at My Pet Chicken; my only complaint was that their site suggested the chicks would be delivered on the second Monday after you order (at the latest), and that is clearly not the case, at least with the less common breeds. You might be able to get RIRs or Orps pretty quickly, though. I also don't know how well their shipping method works with few chicks--if it works, it's nice to have that option to order just a few.