what do i paint the hen house with?

Very impressed! Looks lovely.

I'd put either a slab or brick in each corner to keep the wooden feet from coming into contact with the damp ground and causing them to rot. Also gives you a little more height if you need it.

I assume you've got access to the nest boxes?

Looks really good, and nice and big.

We've at the same stage, but have gone for external ply as the walling. It doesn't look as good as yours, but I was hoping less joints would mean less mites.  We've nailed and glues all the joints with polyurethane wood adhesive, which is really strong, and also acts as a filler - again with mites in mind.

I'm paranoid about the little whatsits.
Good tip re soaking with poultry shield.  I have some, but wasn't entirely sure what to do with it!!

Just posted some pics of our work, but had to reduce the size to almost postage stamp.  What am I doing wrong?  How did you get pics that size to work?  Please explain...... slowly........ as though you were talking to a 2 year old.......

Keep posting, and we can compare progress.