duck house: ventilation vs insulation?

My runners did not thrive below 35F, so they have a pen in the walkout basement, where it stays above 40F all year.  This also helps on wicked hot days, as I bring them in midday if I feel they are too hot.  Yup, I spoil them.  Happily.  Unashamedly.

So, they have an outdoor house, that is a 4'x8', 4' high double-walled plywood box.  I used vermiculite and perlite as insulation because they do not mold and mold is bad for ducks.  They also do not gas off if there is a fire, unlike styrofoam insulation.

All gaps are covered with 1/2 inch metal hardware cloth.  Raccoons climb, as do other predators.  For roofing, I have corrugated panels, one in the center is clear, the others on the sides are smoke colored.  That lets in light.

At the top of the house, I installed plexiglass drop ceiling panels that can slide to open up and let in more air in warmer weather, or seal off the top in colder weather.  It helps keep the house warmer.  I also sprung for an indoor-outdoor thermometer, and placed a sensor inside the duck house to monitor the temperature in there.

I use a variation of deep litter, with a foot and a half of pine shavings and that insulates the bottom pretty well.  I just stir it daily when the ducks are sleeping outside.

I covered the bottom of the house with vinyl sheet flooring that goes up the walls several inches and attached 1"x3" furring strips at the edges to keep poop from going behind and under the sheet flooring.

That also helps keep the structure dry, and is easy to clean when necessary.

This may give you an idea of what I am writing about.

We have a list of predators here that includes

raccoons

coyotes

foxes

bobcats

fishers

domestic cats

domestic dogs

hawks

and more of concern for eggs or ducklings

crows

skunks

opossums

If you are in an area where weasels or minks may be around, I am told anything larger than half an inch gap may let them in.  The forum recently heard from someone who housed their ducks in a shelter that had a gap at the top of the wall, just several inches wide, and something got in, killed the ducks, and scaled the wall to get back out.

I will look for the photo's I have of the hardware cloth on the rafters.  I have hardware cloth over all openings except the doors, and the duck door opens to the veranda, the attached porch, and that has hardware cloth top, bottom and sides.

This summer I have kept the ducks in the walkout basement pen at night because I wanted to shore up the electric fence system and have not done it yet, just too many other things going on.

Here is how I put the hardware cloth in under the roof and between the roof and the tops of the walls.

Since then, I put 2"x4"s along the tops of the walls and laid the plexiglass panels on top of them, to increase insulation without cutting out light.

I have this book and highly recommend it, even though it's mostly about chickens i have used it for my ducks/gees also. talks about the importance of ventilation.
http://books.google.com/books/about/Open_air_Poultry_Houses_for_All_Climates.html?id=o08PAAAAYAAJ Amiga has hit on every thing else especially security just thought you might be interested in this.