Floor covering and mucking out questions

We've had 6 chicks from hatching them, now just come into lay the last few weeks... very exciting.

We have a coop about 1m cube, with a run perhaps 4m x 2m. Currently it's in our concrete car port and the birds just scrat about on the concrete - we pressure wash it once a week or two and that's it.

We're going to move them into our large garden, there's a long retaining wall we plan to tuck the run and coop up against. The strip of land is on the edge of the lawn but is basically bare soil after we removed a MASSIVE amount of ivy, recovering about 3m of garden. It's quite soft and dug up so far.

I'm wondering what preparation to the ground, if any, we should think about doing? If the ground was already turfed would they just tear it up to bare earth anyway or can we compact it down or gravel it or something?And then, what we should put on top of the ground in terms of straw, chippings, etc... and how often to clear them out and what to do with the waste? The place we buy our chicken supplies from has runs on the grass with chippings, several inches deep.