No. I don't think they do. I ordered 4 chicks in July from them and they didn't send any extra. Even all the way to California. All 4 chicks arrived healthy and I am very happy with them.
Some of the hatcheries don't when you order small numbers. If you are willing to pay extra shipping to get a small number of chicks, they figure you don't have room for more birds. If you had room, you would have ordered more birds and not paid the small order fee.