Why are your birds pooping in the nests...are they sleeping in them?
		
		
	 
Yep, that's exactly what was happening.  It was an odd situation.  I had only a couple birds that were interested in the nest box for laying.  At night, I had a couple of birds that would use the nest box as a roost - happened to be my heavier birds. So, I tried for a while lifting the entrance bar to the nest box up at night, preventing the roosting. That was all fine, but then I couldn't be out to the coop in time in the morning to lower it again before they'd want to lay (morning routine/kids/work).  This created a cycle where the early layers would use the floor. Now, it should be noted, even when the bar was left down, some of these early layers would still use the floor. But, the main point being that even if I wanted to train them to use the box, I was sabotaging it by not lowering the bar back down early enough in the morning.
So, researching one day on the site here, I came across some posts talking about poop board and roost bar heights, and it mentioned that for the landing zone, you want clear available space twice the distance out from the edge as the board is high. So, say the poop board is 24" high off the floor, well then you'd want 48" of landing zone distance from the edge for them to fly down.  I got to thinking that when I positioned my boards, I put them at a comfortable work height for me, and assumed that since it felt like a pretty good distance from the edge of the board to the people door of the coop (their landing area) that all was fine.  Well, after grabbing the tape measure and doing the math, it quickly became obvious that if I wanted to follow that rule of thumb, my birds were going to have to be capable of physical feats (flying through physical barriers) that I've only seen done on Star Trek, and even then I'm not so sure they aren't faking it...
Anyway, I lowered the boards down by 8" or so and that brought the end of the landing distance to being back inside the coop - if you want to follow that rule.  It wasn't a big hardship on me, and now the birds have a more comfortable landing zone for getting back down.
The take-a-ways that I think I learned from this:
1. Young birds are pretty adaptable to non-ideal setups because they're still young and agile. Much like kids, they seem to find a way to make it work and not complain much.  My, shall we say, bigger boned birds, while still the same age, couldn't as easily make those adjustments, so they adapted in other ways.
2. We all tease about these birds not being the brightest critters, and in some cases, it's absolutely true - they are just being stubborn.  In other cases, though, they are telling us things by their actions and adaptations they are making in the only way that they can. It's up to us to decipher what's being said by their actions.
3. Similar to #2 - if I come across an undesirable behavior, instead of initially dismissing it as silly bird behavior, is there maybe a reason it is happening?  Sure, you have to be careful here and use some common sense, but they might be telling you more than you think.  In my case, even though my birds were all the same age, the lighter ones were able to adapt pretty easily to the shortened landing area coming off the roost.  The heavier birds were not.  Both groups of birds found solutions.
4. Just because everything is working fine today doesn't mean it's ideal for the long term. This is a bit of speculation for sure, but as the lighter birds in this case aged, their ability to adjust to the landing area may have become more and more difficult.  A good idea when making changes or setting something new up for them to use is to consider if it is usable for all your birds while young and old, light or heavy.  Again, I get that you can't account for everything, and mistakes drive a lot of learning, and that's OK. But, if you can spot something that an older bird might have trouble with, well, a heavier bird might struggle there as well.