Late getting back, but my theory is, they use what birds of flight use to make their "nest". What is available to them in their area. Keep it as natural/low cost as possible!!
Be it oak leaves, pinestraw, itty bitty pieces of twigs etc. Nothing really makes them 100 % happy. They are like human expectant Mother's, they "clean house", (nest) and put a little zone of comfort around them while they eventually stand/squat, and ever sooo carefully, Drop that egg on bare wood!!! Then pick the bedding up around them piece by piece, to nest, as the bloom dries, (and unless they are broody), walk off screaming about the good job they have done!!
I have not got to see all this yet as my chicks will not be old enough to lay eggs for abt. 2 more months.... I can hardly wait!
(Alot of folks believe, as do I, that they carry on about "their" delivery (quacking about, etc. post delivery) of the egg, as a way to distract predators away from the nest of newly hatched eggs and towards themselves.)
I had not heard that about chickens before but I know quite a few animals do that to keep their babies safe!
Of course, if they are in the hen house, then it's a "what's up", ? unless they are just trying to impress the Roo.! But as birds of the wild originally, the distraction kinda makes sense! They sacrifice/chance themselves to give the eggies a chance! Regeneration of the species! Survival of the species. Amazing, humbling, tooo.
Just my humble opinion!
I like it! Thank you for sharing and offering me advice on the nesting boxes!
We did not get the coop finished today. But we used 200' of wire on 1/2 the run. We got the outside of the hens run done and half of the top and ran out of wire. So we have to go get some more tomorrow! We put the birds in the run anyway's! I figured it is not any different than other open air coops. lol and they needed out of the brooders it was just way to cramped in there! Till we get done with the coop we gave them some concrete blocks and some tin on top for shelter up against the coop. They were all so happy to get all that room to roam in! lol