Killed a coyote today and then as usual I covered him in an insectcide powder made for killing lice on cattle. Put him in a plastic bag. 2 hours later when I get home and begin to skin him he still has fleas crawling around. It was -5 here today and I normally use a can of Raid along with the powder but the can was frozen. Any suggestions on what to use to insure a good kill on the fleas in sub zero weather?