This is must my opinion, mind you, but I see that as a really, really nice shed, but not so nice of a chicken house. For that, it needs modifications. To start with, lots more ventilation.....and more light. Perhaps replacing the solid panels on the end doors with hardware cloth? And instead of only one window, maybe three of them and hopefully all of them facing south? Of course all of that is climate specific. Any changes would depend entirely on where you are located. Severity of summer heat and winter cold is a big factor in what changes are needed.
The yard area will quickly turn to mud.......nothing green will be left at all......within a month or so. And with that, there will be attempts at escape by flying out to get to something that is green. Making it larger will help, but it will be a battle to keep them in. Planting bushes in the middle to offer shade will help, but expect this to be not all that tidy for very long. Birds are pretty destructive. It is the nature of the beast.
As for meat birds, I'd be tempted to put them in their own quarters. Something smaller and moveable. They won't be around long anyway. Giving the meat birds their own quarters will also help a great deal with the conditions of the laying birds yard.