The roof needs to be sloping to allow rain to run off. Avoid using felt if this is possible as this is where the red mite breeds. Onduline is a corrugated bitumin which is light and warm therefore reducing condensation. To protect the plywood roof further, instead of felt corrugated clear plastic can be used as it lets the light through and deters red mite which likes dark places. Square mesh is best used on the window and ventilation reas as it is fox proof.
Sectional construction is best for ease of moving.
Nestboxes Located in the lowest, darkest part of the house as hens like to lay their eggs in secret places. Communal nest boxes with no partitions are useful as sometimes all the hens choose just one nestbox and queue up or all pile in together which is when eggs get broken. Make sure there is outside access for you to collect the eggs. They should be the correct height for the breed so they can get on them easily and have room to stand up on them. Make sure they are higher than the nestbox otherwise the hens will roost in the nestbox.