Hello a newbie here, I ordered a "brown layer assortment" from a hatchery. My chicks are a month old now all doing well, but three of them are just huge white birds about four times bigger than the others, I had to separate them. I read that Plymouth Rocks grow fast. My concern is that I am feeding and treating them as layers, and they may be broilers. Any tips on how I can tell the difference? Thanks would appreciate it.