In short, yes it is safe.  The recommended dosage for Stock Plex in a stock tank is .4ppm.  Sheep diets require 5ppm of copper.  What sheep owners need to consider is the total amount of copper your sheep are intaking.  Many feeds have contain copper so while our product isn't enough to harm the sheep when combined with other products used by sheep you could go over the recommended dosage of copper to keep your sheep safe.