Excellent idea, they work well. Make sure you get the sort with a tread on the supporting poles - I bought the Omlet ones some years ago which then just had push-in poles that were harder to insert in hard ground. You may need a few big tent pegs to make guy ropes on any corners as it's important to hold it really tight all round. Also, if the ground is uneven, a few smaller tent pegs helps to hold the netting down between posts, so they don't escape underneath. Keeps them off the plants, and I found the worst problem with free ranging was that they scratched stones on to the lawn, not good when mowing. You can move it all on when the grass gets worn and let it recover.
With new young hens, you may find they fly out at first. I solved this by fixing butterfly netting over the top, tied at intervals to the stakes all round. Then they just bounce back harmlessly. Wing clipping is only partly effective and it would be a pity to do it to your pretty little girls. Once they grow up and mature a bit, they'll probably stop flying out anyway. Before letting them out its a good idea to make sure they're trained to come to the rattle of a box of corn, then they're easy to get back in again. It's good to keep them in their run for several days, so they know where it is and regard it as their home whikst settling in. Too small long-term, but there's no point letting them out in awful weather to wreck the grass. Maybe, when you do let them out, you can fix the netting round the fixed run itself, so they just explore the small local area to start with? Then you could leave the run door open so they can go back in when they want to. Later on, once settled, you can have them a patch further away and they will all follow you and your corn box, like the Pied Piper, between their run and the netting circle - very funny to watch!