Interesting link to Tim's blog here, about how to sex chicks, which he has just posted on Facebook, thanks Tim.
http://blog.poultrykeeper.com/tim-chicken-blog/sexing-chicks/
Is the 'wing feathers grow faster on pullets' just a myth then Tim? I've never bothered trying to sex our chicks, so wouldn't know. With our breeds the cockerels are just as valuable as the pullets- to us that is.