Size of duck house for seven ducks?????

[Hunter0704]

I have three WH ducks and will be getting four more ducklings in March. My ducks are not free ranged and I want to expand the current runs and put a duck house in one of the runs. So, what size do I need for seven ducks? I am thinking about a wood duck house 7 to 8 foot long and about 2 to 2 1/2 feet deep with a door on each front end into the one area, with a lift roof for egg collecting and cleaning. Do my dimensions sound about right? Or do I need to make it larger?

Any advise and suggestions would be appreciated as I want my ducks to have a large enough sleeping space.

Thanks...