My apologies if this isn't the right place to post this question, but one of my chickens has canker and while I'm following through medicating her, I'm also adding acidified copper sulfate to the drinkers for the rest of the flock to help keep things in check (1/4 tsp per gallon). However, I also have a duck and two outdoor cats who use these drinkers - is it safe for them to drink as well?