I bought a house with a pond for my ducks and geese and the geese would never go to the pond. Silly birds.They are going to be put out on the pond? I can just about guarantee they won’t use that floating house they will end up sleeping on the bank which is going to make them very vulnerable to predators. Have they been going outside to get acclimated to temps? I’d not put them out over night with that low of temps but on sunny days let them be outside some to get use to the temps.