For six hens, two 14” x 14” nests would have been plenty. Three won’t hurt and they are built, so no harm done, just a bit of unnecessary construction.
Thanks for that correction, it now makes sense. The photos help too. I’m always an advocate for excess space. If you follow the link in my signature you’ll see some of the things I think are important. Some won’t apply to you but some will. It might help you when you are making decisions on how to manage them. But I also don’t believe in magic numbers for chickens. We are all so unique that no one number can come close to covering us all.
That space is tight. I’m not sure where you are located but it sure sounds like you have snowy winters. But space is not limited to the coop, run space also counts. I don’t know how much space you plan for your covered run, but if you can box off some of it so you keep wind and snow out, you have useable space. That could help a lot on behavioral issues. But if you leave six hens locked in that 4x4 area for extended periods of time you could have some issues. It really is tight.
With the floor space so small, you may have problems with layout. It can be really challenging to have sufficient roosting space and still be able to put water or food in there where they are not pooping in it from the roosts. You may need to feed and water outside. At least the nests are outside which gives you more room. Hanging feed under the coop could keep it dry but you need access to refill it.
You may be able to get away with one 4’ long roost since you have all six hens the same age. Sometimes the hens can get pretty brutal on the roosts determining which gets to sleep where. The more dominant chicken gets to sleep where they want to and can get pretty rough if another is in the way. This is one of those things that you might have a problem or you might not. If some of your chickens start sleeping in the nests you probably need more roost space. A lot of times this is not a problem so don’t get too concerned yet. Just be aware it might be.
Frankly I’m more concerned about the height. Chickens like to sleep on the highest thing available, at least as long as some more dominant chicken isn’t beating them up. You don’t want them sleeping in your nests because they poop a lot at night. Who wants poopy eggs? So your roosts need to be higher than your nests. I don’t know what you are planning on using for bedding but that probably has a thickness to it also. The way I set up internal heights is to determine the top of the bedding, then position the nests, then make the roosts higher. But there is another consideration. You want to have good ventilation in the winter without strong breezes hitting them when they are on the roost.
You need good ventilation in the summer because heat kills a lot more chickens than cold. You need to allow good air movement in summer. It’s fine if a breeze hits them, it’s actually good in the summer. In winter you also need good ventilation to remove bad air. To keep this shorter I won’t go into the why’s unless you ask. But you don’t want a breeze ruffling their feathers. That would allow the air trapped in their feathers and down to escape. The easy way to get good ventilation but keep breezes off of them is to have openings above their heads when they are on the roosts. That way any breezes go over their heads. 3 feet just doesn’t give you much room to work with.
A good way of providing good ventilation is to leave the area under your overhang at the peak and low spots open a few inches, covered with hardware cloth to keep predators out. I don’t know if you have enough room for that or not, but maybe since your nests are so low. A cupola or roof vent may be a good alternative.
Are your pop door and other openings high enough that the chickens won’t be scratching out the bedding?
With good management techniques you might be OK but you are tight. Since most building materials come in 4’ or 8’ dimensions, how hard would it be to knock an end out of that and extend it four feet? And maybe build that section a bit higher? I’m not going to tell you that it is absolutely necessary, it may not be, but most of the potential issues with space are more for your convenience and to lessen your stress level than it is about the chickens. As I say in that article, the more I crowd them the more behavioral problems I have to deal with, the less flexibility I have to deal with anything that comes up, and the harder I have to work. You are important, take care of yourself by giving them enough room.