Harry, Epernix is very safe to use, but when I treat my flock no one is sick. I don't want to be responsible for something going wrong with Scar face, I am just suggesting what could be used to treat internal and external parasites. If your worried then I'd take some poop into a vet and let them do a fecal to see what kind of parasites your dealing with. You dif don't want a huge load dying all at once in him, that may cause some problems for sure. if your just wanting to kill off the lice then you could just dust him but I don't know . efficient a dusting on a gander would be trying to get all his feathers dusted. then your still going to have to treat from internal parasites. I don't know maybe do more research if your apprehensive.