Craig made our nesting boxes from recycled wood and we have two for our chickens.
It's an interesting example of behaviour when the fowl are ready to sit and they check out who is on what nest and a bit of juggling and jostling goes on. We like to situate the boxes so they are not facing the door, turned and a bit dark and private. I think it's a time of vulnerability and the last thing you want is a predator coming upon you. I also believe when passing an egg you would appreciate a bit of dark and quiet.
When I clip the poodles I have at least a shopping bag packed with soft hair (not fur). Because it is quite cold here it is rare to have flea cycles. I have only ever seen fleas here on our dogs once in the last 25 yrs. The dogs are only clipped after being freshly washed and they use the same products I do, pure home-made tallow soap and vinegar herb rinse.
This makes a beautiful soft and insulating nesting material.
I also sprinkle some huon pine shavings in the boxes to deter insects.
Nutritionally do these sort of things improve the egg quality? Probably not but I believe that working with an animals proclivities rather than against them makes for a happier animal that stays healthy and produces well.