I was looking at Cx from a hatchery (I forget which one to be honest) and they had Cx FAST growing and Cx SLOW growing... The slow growing ones took like 10-12wks and I believe dressed out up to 6lbs, while the fast growing took about 6-8wks and dressed out up to 8lbs. It is quite possible that you got the "slow growing" genetics, even though they weren't listed as such, because that's probably the only type that hatchery has.
I'm looking at $42 for 25, straight run. BTW, how long did it take from your order until they shipped? I'm looking to order 25, but really need to get an outdoor brooder or something setup before ordering, but don't want to wait to order, only to have them take a month to fill my order.
Hmm. I wonder if I should just order, then if they come right off the bat, I can keep them indoors for a day or two until I can get them going outside. I can always use the kiddie pool for a few days.