So I've read that it's a good idea to give new chicks a plug of sod to expose them to your local coccidia while they are young. Lazy Gardener might be who I noticed saying this. Plenty of sense in that and I did so with my fall chicks. I have eggs in my new bator now and I'm wondering how this applies to winter. Give them half frozen dirt, seed their bedding with coop bedding, dig under coop bedding to get dirt? I have bird feeders in my yard that are possible hot beds of local bird "bugs", use dirt from there? Or none of these is useful? Thank you.