Depends on what you mean by optimize. I mean, if you free range you don't dictate where the poop goes, but it's the easiest way to get poop everywhere, as they put it there without your intervention.
With a paddock the poop is concentrated and you have to move it where you want it.
Chicken tractor it's concentrated again but you move all the chickens to get it where you want.
So what are your needs and what kind of labor do you want to put in it?
I free range but believe I'll probably pen them up eventually. They aren't doing as much as I want them to be doing, we still had grasshoppermagedon, stupid birds. They also ate a lot of my garden. However, it's nice seeing them run about and they do go churn up and fertilize ground. They did a nice amount of work for me this fall with turning and cleaning out the strawmulch I put on the garden. It shouldn't have any weed seeds or bugs in it.
I doubt I ever chicken tractor. I'd have to build something to do it and I'd probably forget to move them. Too much labor for me.
I already have a fenced pen so penning them would be no problem. I haven't' done it yet because I love looking out my windows and seeing free chickens ranging all over the property.
I vote thumbs down on free range! The chickens just make too much of a mess for me and have a tendency to cause more damage than they do good. The chicken tractor works pretty good for establishing garden beds, but once you've got your beds set up they can be more trouble than they're worth (and I agree with Elle on the amount of labor), and you can't move the tractor back into the area easily once things are growing(which you might want to do for pest control and reapplication of manure). I would opt for a rotational paddock system where you can pulse the chickens through and area, establish your beds, move them out, and then plant and not return until your plants are well established and can't be damaged too much by the chicken activity. Make sure you have enough paddocks that you can wait quite a while between moving them through again.
that is what i was thinking is a paddock system, i don't like the idea of caging my chickens anymore than i have too( at night). i am just looking to regenrate my soil to establish more garden space. i basicly live on a pile of dirt so i have a lot of work to do to develop some good soil. thanks for affirming my thoughts!
Having tried all 3 methods (1000 birds this year) go for the paddock, buy electric netting.
Still aerial predator problems but they snitch birds...not exterminate. Kencove makes the best netting I've found
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