Even down here in the south my Muscovy's have gotten frost bite on their knobs both have healed but the skin is thinner and my female ripped hers open last year so she walked around with blue kote on her lil knob for about a month. Maybe mine are rotten because in winter about the only bathing they really like to do is splashing the water out of their heated buckets. I put out cement mixing tubs and usually my geese and other ducks use them more than the Muscovys. And this year they did spend a lot of time inside by their own choice to get out of the brutal wind chills down below zero a few times. Probably depending on where in the world we are keeping Muscovies depends on what they can take in their living conditions just like people we acclimate to our surroundings.