A few can love a dog house, if you only lock them up nights. They are very winter hardey, but they need protection from all preditors, especially at night. Dogs love them. The term "sitting duck" meaning your about to get killed, well, its apt. Ducks aren't good self defenders. If you have a secure back yard, and no stray dogs or other large animals can get in, your back yard will be fine. If you give them a house, just to go in, they will pretty much never go in it. I have to walk my ducks in at night, unless its light is in and they are used to going in. Mostly, by choice, they prefer outside.