Great minds think alike. I always dig up chunks of sod and toss those in the brooder. They quickly learn it isn't as terrifying as they thought, and it helps to get them started on building a good immune system. I've never used medicated starter either, nor see any signs of coccidiosis.No doubt! Now, I have to figure out how to let them go outside without losing one or two, they are so wild. I have a Great Dane size dog cage, not the one Bodie is going outside in, but a larger one. I just have to reassemble it and put it in the pen and transport them into it. As they get larger, they can be loose, but large as they are at this age, they're still pipsqueaks in the Great Outdoors, hawk bait.
I have an kitty litter pan that was never used so I can dig them up some good dirt and put the pan in their pen inside the barn as well. They've already had dirt in a pan in the brooder from a week old, but the pan is way too small for that number of chicks this age. Gotta stave off coccidiosis, build their immunity. I hope I don't have to deal with that, rarely ever happens with broody-raised chicks. I haven't had to treat coccidosis in umpteen years. If I do, I'll have to buy a new bag/bottle of Corid. I don't use medicated starter which doesn't always work anyway at the maintenance dose that's in there, especially if it's very damp in the environment. Most here on this thread know all that, of course, but you never know who is reading on the platform.