It's new, and strange, and scary. And it might hurt them. And yes, it's cold on their poor little feet. Mine would not leave the coo after the first snow. I finally enticed them out by throwing some scratch on the snow. But that was just a very small amount, less than an inch. More than an inch and they wouldn't come out again. Until I shoveled their ramp. And the run. And threw down some straw for them to walk on. Now the spoiled things don't want to come out until after I've shoveled and raked up the straw or throw fresh straw down. But they have gotten used to the snow enough to venture out of the run with an inch or so on the ground. Of course, they venture out and then prefer to hang out under the saw horses on the patio where there is no snow. But I've found their little chicken footprints in the snow all over the yard. But I do think it does get cold, because even when given the option to come out they tend to prefer hanging out in the run where the straw is. And the first time I threw straw down I felt warmer standing in the run!