You have to stay on top of them almost everyday. Mainly after warm rains. We use a powder, that we just place on the mound and in about 12 hours they are dead--(That Mound). We also use it in our fawn pens with newborns. To my Knowledge, we have never, had it effect fawns. I have seen some fawns almost laying in it. I can post the make of it when I go to the barn.
If my parents read this they might post it before I do. Hope this helps. Jay Don