One reason you see so many different opinions is that different things work. We are all unique in our own ways so there is seldom any one way that is “best”. There are many things that are equally good but perhaps something unique in our goals, climate, management techniques, or set-up makes one a little better than some others but that is not going to be best for all of us.
For example, different people might use wood shavings, straw, hay, shredded paper, Spanish moss, carpet, rags, or something else for bedding material in nests. They all can work but we all have our preferences. I gather tall grasses that have gone to seed and use that, technically hay I guess, because it’s free for a bit of labor and readily available. Since it’s free that’s best for me. Someone else on here uses cloth chicken feed bags. For him, those are best.
So one bit of advice is don’t get too fixated on something. Remain flexible. Consider about everything you read form anybody, including me, guidelines, not laws of nature.
Chickens like to sleep on the highest thing available. Chickens poop a lot all the time but at night they are not moving around so poop gets concentrated where they sleep. I don’t like poopy eggs so I don’t want them sleeping in the nests. Moral of the story, make your roosts higher than he nests or any place else you don’t want them sleeping. Don’t put feeding and watering stations under roosts.
In a coop you size this is probably not going to be a concern but the higher the roosts the more open area they need to spread their wings and fly up to the roosts and fly down from the roosts without banging into something. Some people worry about heavy breeds injuring themselves when they jump down to the ground but I believe (my opinion) that it’s not that much of a risk as long as they have enough room to fly down. Still I suggest you make the roosts as low as reasonably possible and still have them obviously higher than anything else. The way I position roost height is to determine the top of the floor (including any bedding), then position the nests, then make the roosts higher than the nests.
What is the “best” nest height? Wherever they are most convenient to you. Some people put nests, maybe a cardboard box or a cat litter bin, on the floor and call that good. People with bad backs tend to put them high enough so they can get the eggs without bending over.
Chickens scratch a lot. If you put the nests on the floor they might scratch dirt and disgusting things into the nest unless the sides or any openings are up high enough. If you hang the nest up a few feet a perch in front of the opening may be beneficial. We make nests all kinds of ways. Some people will try to give you rules for nests but if you look through a few threads on some of the things we use for nests you’ll see that they are not really rules that must be obeyed, but suggestions. These are just a few of those threads.
Opa’s Rollaway Nest Box
How many nests do you need for 30 hens? There are rules for this but you know how I feel about rules. A number often given is 4 hens per nest but that takes into account none of our uniqueness. I think size is important. That four hens per nest rule is probably not a bad number if you follow the rule of the minimum size nest being 12” X 12”, so 7 or 8 would work. They will mostly use just a few anyway.
I made my nests 16” x 16” x 16” tall. My stud spacing is 16” so that was a convenient dimension for framing the nests. Also, if you cut a 4’ or 8’ piece of wood or plywood into 16” pieces you have no waste. There have been plenty of times I’ve seen e hens in the same nest at the same time. That’s hard to do in a 12” nest.
I like building flexibility into my facilities. I made a couple of my nests so I can lock a chicken in there if I want to. That’s come in handy several times. I built a 3’ x 6’ brooder with wire bottom in my coop. In addition to being a brooder, it serves as a broody buster or a place to isolate a chicken if I need to. My main run is 12’ x32’, pretty predator resistant. At the far end of my run I have a 4’ x 8’ grow-out coop with an 8’ x 12’ section of that main run fenced and gated so it can be isolated from the main run. That gets used a lot. In addition I have an area maybe 45’ x 90’ inside electric netting. That netting area has a 4’ x 8’ box (I hate to call it a coop, it’s just a box) in it that gets used occasionally. I hatch most of my chicks with an incubator or broody hen so all his fl3xibility comes in real handy.
Now for some suggested reading. You might follow the link in my signature to get some of my opinions on space requirements. These other links can be quite informative. I think everybody should read them.
Pat’s Big Ol' Ventilation Page
Pat’s Big Ol' Mud Page (fixing muddy runs):
As far as getting it right, I suggest giving them as much room as you reasonably can in the coop, in the run, in nests, on the roosts, just anywhere room comes into play. Squeeze them too tightly and you can have consequences you don’t want. Also keep everything as dry as you reasonably can. A wet brooder, coop, or run is a breeding ground for diseases. When the weather sets in wet you may not be able to do a lot with the run, but do what you can.
Good luck and welcome to the adventure. It’s a fun trip.