[Flowerpower136]

Still in construction mode, and was planning to roof the hen house with corregated bitumen, which I thought would keep rain out, and provide the necessary ventilation with a constant flow of fresh air at roof height.

Assuming that will be sufficient for summer.  What about winter, will it be too cold/draughty?  I could always insert a 'false ceiling', but trying to avoid any unnecessary extras that might encourage mites.

Can I have some examples of good non/draughty ventilation please.

[andreadon]

make sure the ventilation is at the top of the house - working on the principle that hot air rises and cold air is dragged in from underneath.
make sure there are no gaps around at the bottom.

your best bet is having a roof with an overhang and having the ventilation holes under that.
in summer we lift the roof of the house up by about 2 inches by lodging blocks of wood under it.

in winter we just put more straw in at the bottom!

[Timbo47]

I've read in various Mags & Books that Hens can withstand the cold , better than they can the heat. I've just built a Hen house and used the bitumen Green roofing...I get Hens on Saturday, so i hope I've enough Ventilation too.....watch this space

[andreadon]

I've read in various Mags & Books that Hens can withstand the cold , better than they can the heat.

you're right - they only have little tiny heat dissipators on the top of their heads but big feather duvets!
they hate draughts, that's the only thing.

[treacleminer]

An extra thought - with corrugated bitumen (I have this) there are sufficient gaps for vermin such as weasels to get in, so make sure that you have something like weldmesh underneath it preventing them.

[GrannieAnnie]

We were given some onduline, only had to buy 1 sheet to make up what we needed.  And I said to Brian that we'll have to get some weldmesh to stop vermin getting in.  Would you make it fit around the bottom of the corrugated sheet, or just sticking out at 90°C?  would they climb over it I we did that? 

With regard to ventilation.  although Our big henhouse had 3 decent sized vents plus holes drilled along the top of one section, it still wasn't enough as we used to get a lot of condesnation as 250 chicks create a lot of heat!

so Brian took out the 2 blacked out windows and made louvres instead, and its wonderful.  No condensation, no draughts and still dark because of the position of the louvres.  We also covered them in weldmesh to keep the vermin out.

[Flowerpower136]

Thanks everyone.

Eggcellent advice as ever

Good tip re weldmesh in the correguated gaps, hadn't thought of that, but that's what we'll do.