we did exactly this.
i built a house and run for them, which they lived in all the time… we let them out sometimes at weekends, but it was impossible to leave them out when we weren’t out in the garden because we couldn’t stop them getting out of the yard.
to be honest… it wasn’t great. Because they were in such a small run (approx 3x1m with bark chippings on the floor) their poo overwhelmed it… the run stank and needed cleaning out every day. When it rained, they got covered in bark and crap and looked miserable.
They started getting quite bald, and appeared to be stressed and pecking each other. Our neighbours told us that foxes and cats were tormenting them when we were out – apparently a fox would sit outside their enclosed run and stare at them, with them going mental inside.
One weekend we forgot to bolt the little hatch that we used to get the eggs out – when we got back we found a scene from a horror film, with 3 dead hens and blood everywhere – the fox had squeezed itself in and killed them, but didn’t even have the decency to get a meal out of it.
We decided not to replace them, as it just felt like it was cruel keeping them.
Sorry if this isn’t what you wanted to hear.
Dave