The bale method seems like a lot of work for me, but if it works easy for you that's great. Truly! I'm a big fan of more natural gardening so I'm glad you mentioned an alternate idea.
My method: I use 1"x8"x2-4' non-treated pine boards & 'paint' them once yearly with old olive oil. I do this more to keep the wasps away as they like to chew old wood & I very much dislike wasps. For me it holds up well, they don't fall apart or rot easily for upwards of a decade. The old wood can then be buried to rot in a new growing hill or used for firewood.
But we're derailing a bit! Do you have any vids online of your quail tractor? Maybe to show us how you drag it to different spots, or how you cover the bottom to prevent crushed eggs & hurt feet?^^