Question for all ya'll big bird raisers... I have LF Cochins, LF Dark Brahma, and now have 1 roo and 3 blue jersey giants pullets. all big birds.. I have raised big dogs we'll forever and we always take them off puppy food earlier than large or med dog breeds because it can make their bones grow too fast and then there can be problems with their legs joints etc.. is it the same with my birlds.. the oldest are the dark brama hens and they 5 months old.. only i=one is thinking about laying, she isn't yet but I figure the lLF or giant breeds mature later due to their bodies working on size as an importance to breeding or laying.. my blues are still you'ins.. only 4 weeks old.. ( I call them my pterodactyl 'd ) .. oh my gosh do they love food of any kind.. non stop eating machines. but like I said used to raising Danes so I expect the large food intake from them.
If your birds are from a hatchery I'd feed them like any other chicken. When I first got into chickens I got myself some hatchery Brahmas, and, well, they were hardly any bigger than the rest of my chickens. Then I got some non-hatchery Sussex and some non-hatchery Brahmas and wow! HUGE size difference.
If yours are not from a hatchery or hatchery stock, try feeding them lower protein feed, as for intake, I've never known larger breeds to be dangerous eaters like Cornish X, so, feed them what they eat.