We live in Michigan and it has been very cold and sporadically snowy. Every morning I let our flock out to free range. On cold snowy days i shovel a path from their coop/run to our large covered back porch where they hang out for the day. If the weather warms they wander if its cold they stick to the porch area. When evening approaches I have noticed that 1 or 2 don't return to the coop with the others. Which is not their normal behavior. This seems to be when we have snow on the ground. I wonder if the bright snow interferes with their perception of darkness. Anyone else with this problem?