There is one thing worth checking, that is the copper content of your soil. Most agricultural stores have the means to test.
Goats require almost the same copper as a cow. Most goat minerals in the ready made compounds err on the safe side and are generally too low in copper. If copper is a problem in your area, the solution is simple and also cheaper - feed cattle dairy nuts. I never feed anything else - my black goats are very black and my milk yields are excellent.
It is incredibly difficult to overfeed copper in this manner - goats can get rid of the surplus they don't need.