I have two BRs now 8-9 mnths old. Although it is cold they are not eating much. I have tried all sorts of things mixing shaved suet, sunflower chips, small amounts of cracked corn and boss into their layer pellets, sometimes with a little warm water or yogurt, but they don't eat much. They also have dry pellets on a free feed system. I have started mixing electrolytes/vitamins in their water as I don't want them to get sick in the cold. Is this OK?