I agree, unless he's getting commercial stock, the price is a little low.
People put up adds at our feed mill at times, looking to partner with others to meet the 25 bird minimum, or to get discounts at 100, and the prices are not that low.
I think those pics were pulled off Cackle Hatchery's web page:
http://www.cacklehatchery.com/whtleghornpage.html
Edit: Yes, that's where the pics are from, I thought they looked familiar.
Cackle's price is higher than he is asking on the pullets, but lower on the roos for orders of 100.
Maybe it's a legit offer and he's getting a good end of season price, maybe not. Wouldn't hurt if you don't pay up front, unless you get stuffed with a bunch of roos when you buy pullets through him.
Personally, I don't buy anything from people who can't understand how and when to use a caps lock key.