I agree with the others on genetics aspect. However....
Alot of it also deals with conditioning though too. If you have some of the cockbird's favorites that are getting overbred constantly, they are going to be missing crests, cushions, and alot of the back feathers too. Some of the broody hens will pick out the feathers along the abdomen. I have 1 pen that is all missing their beards because I have a feather picker in there. There's a huge reason that most of us that show, keep all pullets separate from cockerels as soon as we know who is who. The cockerels we plan on showing are kept in individual cages. The adult breeder stock usually has the crests and cushions severely trimmed for breeding too (unless you plan on AI'ing everything). When I shut my incubator off in June, I pull all cocks out of the breeder pens til after the fall shows and give all of them a break to recuperate and get their feathers back. If you have the birds out on rocky ground or even wire cages sometimes will break those foot feathers off really bad. If you let them out in direct sunlight too much, you are going to have brassy sunburnt feathers.
Its why I try not to get too hasty in calling anything 'hatchery' stock. I have some birds in my breeder pens right now that I know by legband and wingband numbers that placed at some fairly large shows up here. After being in the breeding pen for a couple months, you wouldn't recognize that bird right now. After breeding silkies for 10 years, I know that they don't all look like that 365 days of the year. Its why most of the birds in the show ring are cockerels and pullets. Your older stock is a guessing game to see if they will even be in condition at the right time.
