In order to answer your question some information on your chickens is needed like what breed(s) are they and could you tell us their age. Also you mentioned you were feeding laying mash, which, as I understand it, mash is fed to babies or teeny-tinys when their throats are too small to swallow anything big, and as your pullets grow, the feed is changed from a mash, to a crumble and then maybe to a pellet feed. "upgrading" feed as your chickens grow enable your birds to eat more easily and more efficiently. Larger feeds also reduce the amount of food wasted by the chickens, so you know your birds are getting more of the food you are feeding. That's where I would start. Good luck.