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
straw mulch 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.