What is the best material for nesting boxes? Do you keep the next boxes covered all the time?
I use shavings or dried grass clippings or hay... whatever I have on hand at the time.
I use lots of different nest boxes (whatever is available). They're not covered.
I have an old bookcase that I stood up inside the coop and the hens use this as their nest "boxes."
I guess you can say they're covered since the shelf above covers the shelf below.
I also have a large garden planter on the floor of the coop that my hens love; it's not covered at all; just in the corner.
I also place cardboard boxes around my pole barn in case the hens want to lay an egg while outside the coop.
I do not use straw as a nesting material since mites like to live inside the straw.
I've used straw and pine shavings and both work ok. My girls liked to pull the straw out of their nest boxes and into their coop which I didn't like. I clean my coop every morning and was constantly picking straw out of the manure making it more time consuming to clean. I want straight manure with nothing else in it if possible. My wife is big into flowers and flower gardening and we use the manure to make a manure tea to water her flowers with and the straw mixed in it just caused problems. Pine shavings worked better but they still pulled a few out, ate some and I didn't like scratching them off the eggs that were stuck to them. I ended up using a piece of carpet inside each nest box and so far that's worked the best for me. I've used carpet for a couple of months and so far I've had no problems with it. Now the eggs are a lot cleaner and it cushions the egg from being broken.
Pine shavings. No issues.
I use pine shavings, which I buy in a big bale from the local feed store. The hens lay in 2 corners in the coop (one corner is a shelf above the other corner, so they're both technically "covered" areas), as well as in a pet carrier underneath the chicken coop (the floor of the coop is about 3 feet off the ground. I used a couple of fake eggs to get them to lay in the pet carrier; it was amazingly, quickly successful .
Joni in CA