There are lots of different ways people use tractors but in general, you need to supply all you would in a normal coop and run. They will get nutrition from the stuff in the tractor but they cannot roam enough to get the variety of grass, weeds, grass and weed seeds, decaying vegetative matter, and all the creepy crawlies they would if they were free ranging. Most of us don’t have the variety of foods they need to totally support themselves by foraging even if they could totally free range.
That means you need to provide feed in the tractor. You need to supply calcium. They might get enough calcium from the plants and creepy crawlies they eat but it’s not likely. If your basic rock is limestone they will get some calcium from the rocks they eat as grit, but I strongly suggest you offer a calcium source like oyster shell on the side even if you feed Layer.
They should pick up enough pebbles for grit from the ground. You can offer them grit if you want but I wouldn’t bother. They are really good about pecking at the ground and finding grit for themselves in practically any soil.
When I kept mine in a tractor they were in there 24/7. I had a roost area built in. You can keep yours in there as long or as short as you like. There are no rules about that. It’s up to you as to how you manage them.
