What are some signs of copper deficiency? I need to go to the feed store and if my guys need copper I would like to know so I do not over dose them. Last owner had loose minerals for them and right now all I have is a salt block with minerals and copper. They are not licking it much. The older doe seems to but the babies are not. At least I haven't seen them lick it. When looking at loose menirals, what should I look for in the copper content?