Hi - this is my first winter with ducks and this morning there was an inch of frozen ice over their baby pool pond and there were ice shards in their covered secure night coop. They sleep in a coop made out of plywood, no insulation but they have about 6 inches of shavings. How cold is too cold for ducks? I want them to be happy and comfortable. Do I need to put them in the garage at night when it's this cold? Does it hurt their feet to walk around on frozen ground? They seem happy but it just seems so miserable outside. Any other cold weather preparations I should do? Thank you!