I am a new duck owner and this is my first winter with my 2 girls (Pekin and Rouen). I noticed some ice on their feathers and immediately panicked. Is this normal, should I try and bring them in to melt this? Is it okay to put them back outside after I dry them? They have a shelter outside that has a deep litter of straw and a heat lamp. I thought a night under the heat lamp would help it, but nothing happened. Worried new duck mom.❤❄