Here are some photos of the inside of the hen house - we adapted it from a 5' by 7' shiplap shed. I cut a whacking great (for a chicken) hole in the side with the jig saw (aren't they great?!) that has a fastenable door; and then put in a perch with a droppings board underneath. This is because it makes it MUCH easier to clean out - chickens excrete two thirds of their poo at night, so you just have to scrape the board off every so often and they don't end up scratching around in their own whatsit so much.
You can see the nest box underneath, with modesty curtain - they like to lay in the dark. I think that that's Ginger in there, having a quiet moment.
We have a ladder for them to get up and down, but mostly they just fly up and jump down. And their food (layers pellets) is in one corner by the door and the water in the other. We found that in the very cold weather in the winter the water did freeze - and we lined the roof of the house with bubble-wrap; However, I don't think that that was really necessary for the birds, as they are very tolerant of cold. It just made me feel that I was looking after them.
I like the converted-shed idea because it makes it SO much easier to clean out, and to get in there to handle the birds if you need to catch them - you have proper head-room, which would be big-bucks if you were buying a 'proper' chicken house.
The seven laying hens and Dennis the Cockerel live in here. I would be happy to have another two or three hens in there as it stands; but any more than that and one would need another perch. You are supposed to allow 15-20cm of perch space per bird (depending on the size of their breed) and a couple of square feet of floor space each. In theory this would mean that we could accommodate 17.5 chickens; but I think that that's quite a lot in this kind of space, really - it's good for them to have a bit of room inside the house. They like the mixture of straw and woodshavings that we put down on the floor because they can dustbath and scratch around in it when it's too wet to go out.
We have made them a pen outside, too. Largely because now the garden is growing, their great big chicken-feet are death to any seedlings. And they seem to like to dust-bath in freshly dug soil. So we only let them out for a couple of hours in the day, mostly when we are around. The rest of the time they are pretty happy in the pen. It's about 7' by 15' and is based with concrete slabs and has straw in the bottom.
You can see that there's a pile of logs for them to perch on - which they like to do in the evening before they go to bed - and a grit-dispenser hung up so that they can take a peck at a bit of grit or oyster shell when they feel like it, to help their digestion or their egg-shell strength. There's also a Belfast Sink full of soil and the idea was that they could dust-bath in it; however, they seem to prefer to perch on the edge, and dust-bath in the house.
It's important to have a sturdy floor to the pen, so that foxes can't dig up-and-under. DEFRA regulations (if I read them correctly) say that to be defined as 'Free Range', your hens should have a square yard of outside space each (ie, 9 square feet). That, IMHO, is not very much at all. It would mean that in this pen, we could fit 11 hens. And to me that's not 'free range' at all. So that's the absolute minimum I would recommend in a pen. It's obvious that the hens are bored when we keep them in - their egg production drops off a bit and when you pass by the pen they all rush to the gate, in Chicken Excitement. They much prefer being out ranging round the garden; so I am looking forward to getting the vegetable beds sorted so that they can amble round again all the time. As a poor substitute for going outside, we take a piece of string and hang up a cabbage, or the lettuces that bolted when I briefly turned my back. They can spend an afternoon jumping up and pecking at it in turn and then jumping back to dodge the swing - a bit like swing-ball for chickens actually, only with brassicas.
I'd better go and shut them up in a minute - I chuck a few handfuls of corn in to the pen and they all troop in and I shut the door. And that's it - time for bed.