Hi, Don't worry! They will soon tell you if they don't have enough space by ganging up at the gate into the run and/or you will see them pecking each other, which chickens do when penned too closely. Chickens are hugely sociable animals and normally love to be together. We also have had to pen our free-rangers because of bird-flu but they remain healthy and happy. As to bugs for them to eat, if the run is on grass you don't need to do anything. The bugs will be there. If it is on dry earth, then might I suggest putting down a load of leaf mould? Our chucks love the scratch among the fallen leaves where a load of bugs live. Maybe move your compost heap into the run? Our chucks adore the compost heap.Last year we moved out of city limits onto 2 acres and got 8 hens in December with quaint dreams of the chickens free ranging around the property while we were out working "alongside them." The coop that I built was from a design I found online and only had a small-ish (8' x 4') run.
After a couple months of free-ranging it became a headache being worried all the time about where the hens were. Moving from the suburbs, 2 acres felt gigantic. I thought chickens would be too "chicken" to venture far from their coop/home but we have neighbors on 3 sides and the hens kept wandering off into their yards and getting chased by their dogs. I also got really worried they were going to go into my one neighbor's garage while he had it open and poop everywhere (like they did in our garage - which was making me have to remember to keep the garage closed at all times, which also meant I wouldn't be able to work comfortably in the garage in the summer when it will get hot). I found myself constantly glancing out the windows to try to account for the chickens and getting worried (about them having gotten snatched or just wandering too far into a neighbor's property) if I couldn't spot all of them. We also had to wall off the deck so they couldn't get up on it and poop everywhere, and I have had to spray off the front porch every day or two. We didn't want them free-ranging when we were all gone from the house, so going anywhere with the family required a new chore of rounding up the chickens back into the run, which I felt bad about on days when we were gone all day bc the run seemed small for them.
Long story short, just yesterday I finished building a new run that attaches to the old run. I felt so bad about penning them up and hopefully made it large enough (16' x 20') that it will be comfortable. So now they have the old 8' x 4' run and the new 20' x 16' run as well as the space directly under the coop which is screened in (5' x 6'). Today is their first day not free-ranging and I would love some encouragement that I'm not ruining their lives.Hopefully in the future we can get a fence around our backyard and let them free range again "part time." Is there anything I can do to encourage more bugs in the run??