Ventilating a "Sleeping bOX"

I have a pen for silkies that is about 6x 16 I am keeping a dozen in there. I would like to design the pen more in the way they did in the "old Days" when they had a coop and a scratching shed. The coop is not insulated and is usally about the same temp as out side. I want to build an insulated box that is, about 4feet by 6 feet and 3 feet high as a "sleeping Box" A place for them to huddle together. So I know that I need a pop hole that is about 8 inches square for them to go in, and I am an electricain so I will be installing some themostaticly conntrolled heat in that box to keep it above freezing. The cover will be hinged and I may keep the waterer in there to keep it water instead of ice or I may just use a heated dog dish in the other part. The problem I have with the bowl is that they get thier crests all wet, so I was thinking a chick fount in the "Sleeping Box". The rest of the house would be covered with shavings with the feeder, a dust bath, and some scratch grains to get them moving thier feet. Then they have to choice which part they want to be in, as they can just come and go. The problem I see is I don't know how to ventilate the "sleeping Box" I know I would need to change the air in there to keep it dry. I know that the hot moist air rises, So I am thinking that I need to put a 4" X10" Floor register in the roof of the box, ( or maybe two?) and the cold air would be drawn in through the whole that the chicks come in through. The other choice that I have is to put a 50 cfm bathroom fan right in the cover to take the air out. Which do you think? is there a better way? I am not sure if i should put the chicken door in the middle of the 6 foot wall or off to one end? or maybe two doors so they can't get trapped in there? should the ceiling vents/fan be in the middle or off to one end? Any advice or expericence that you could offer would be great> Thanks

 

Thanks for the help.

Do you think it would make better sense to have the floor in the "sleeping Box" just a flat floor with pine shavings? Or would it be better for them to have a 2X4 on it's edge on the floor for them to Roost on? The only reason I was thinking about putting the water in the box is to keep it from freezing, but Maybe I can come up with a way to keep chick founts from freezing in the main coop. Does anyone else have a problem with silkies getting their crests all wet when they drink out of dishes? Is there a way around that? like maybe covering a heated dog bowl with a piece of plywood that has small one inch holes drilled in it for them to drink through without getting wet? Just a thought, maybe there is a better way. I will have to get my "google" fingers going later and see what is out there.

Thanks,