A lot of them are selling out early and have huge back order schedules this year. I'd also had issues too with looking and tons of hatcheries. I think probably all of them are like that. :S
4 weeks is pretty good to start seeing the wattle show. That's enough time to find out pretty early still. And because of the 'The KFC Finger Lickin' Good Principle', scientifically you won't go wrong anyway, as you can put any rejects to good use.