"tractors" in the winter?

[hfchristy]

This is our first winter with our ducks. They have a house where they stay at night, but in the daytime they move to a separate pen that travels the yard. They have no way to get from one to the other unless we open the doors and herd them. This has been working fine so far, but I'm worried about the colder weather coming. I know that ducks are pretty cold hardy - but since they are caged up and can't move out of the wind into a more sheltered area, or follow the sun around the yard, I'm not sure how much I should count on them being able to tolerate.
Right now they have a tarp going up one side of the pen and part way across the top. That decreases the amount of sun they get, but they seemed skittish about birds flying overhead, so I wanted to give them some way to "hide". Besides the reduced sunlight, I worry a little that a big snowstorm could put more weight on the roof than it can really hold. I'm guessing that the wind would *probably* blow the snow off before it got that deep, but having not tested that theory yet, I can't be sure.
Should I put plastic all the way around the lower portion of the pen?
Try to find some way to have an insulated spot in there that is contained, yet light enough we can move it around easily?
Just give up on moving it when the ground is frozen??

Thanks!
Christy

 

[hfchristy]

We're in Rochester, NY, so not an "extreme" climate, but we definitely do get "real" winter weather here, and the yard is flat and windy.

Christy