The way I determine elevations. First, determine the height of the coop floor including any bedding. Then install the pop door higher than the top of the bedding so they don't scratch bedding material into the run. I made my 12" x 12" pop door about 12 inches above the floor but if I had to do it again I'd go with 6". It's easier for a broody hen to get her baby chicks in and out at 6".
Then I'd install the nests. Some people like the nests at the coop floor level. If you go low you need enough of a lip to keep them from scratching coop floor bedding material (which included poop) into the nests. Some people like to put the nests higher so it is easier to look inside then for eggs, especially if they have a bad back. Or somewhere in between. Chickens don't care but as you can see some people care a lot.
The suggested minimum size for nests is 12" x 12" x 12". That should work well for your breeds. My chickens are sized similar to yours. I made my nests 16" x 16" x 16". That fit my stud spacing and if you cut a 4 feet long piece into 16" lengths there is no waste. There is no waste at 12" lengths either.
I have two rows of two nests stacked. That takes up less wall space than a single row of four nests. The hens use all of them. Most hens lay in the same nest but that popular nest will sometimes switch around. I've had broody hens hatch in low nests and high nests.
Next I position the roosts. Chickens usually like to roost on the highest spot available and I do not want them sleeping in the nests so my roosts are higher. My droppings board is about 6" higher than the top of the nests. The roosts are several inches higher than that. I use a garden hoe with a shortened handle to scrape the roosts so I have enough room for that between the droppings board and the bottom of the roosts.
Chickens can be hard to catch during the day but at night you can pick them off of the roosts. I'd want the roosts a convenient height for that. I'm basically looking at higher than anything you do not want them sleeping on but as low as reasonable.
In Upstate New York you will have cold winters. They need decent ventilation to get rid of excess moisture from their breathing, poop, and drinking water. Youi don't want a cold wind hitting them on the roosts so your open ventilation needs to be higher than the chickens when they are roosting. I like some openings as high as I can get them, that helps air circulation.
I only have one window in the north end of my 8' x 12' coop. But I have ventilation all around the top, open space on all sides covered with hardware cloth for predator protection. That lets in a lot of light.
Now to your questions. Horizontal layout for 12 full-sized fowl hens. What you have should work well. You need room for you to be able to move in there and work. I'd want the roosts far from the human door so they are more out of the way. Your hot walls from the sun are going to be the south and west so I'd want your nests and roosts on the north and east sides. Other layouts could work but I don't see anything wrong with yours.
Chickens like to roost at the highest spots available. The ones highest in the pecking order sleep where they want to and push the others out so those settle for what is left. Whether your roosts are ladder style with some higher than the others or they are all the same height they are going to squabble over them. Either style can work well. Dad's were staggered, mine are the same height. Chickens used both styles.
My Australorp, Sussex, Delaware, Rock, and Orpington have no problems flying up to a roost five feet above the coop floor. They have no problems flying down in the morning. They don't hurt themselves. Mine do have a clear landing space in front of the roosts but I've had some fly forward from the roosts about 8 feet, hang a 90 degree turn to the left, fly out of the human door, and land in the run. I even had a grown full-sized rooster do that once, almost hit me as I was going in the door. Mine are hatchery quality chickens, not the show chickens that are bred to grow big and are fed to grow big. Maybe that makes a difference.
Then I'd install the nests. Some people like the nests at the coop floor level. If you go low you need enough of a lip to keep them from scratching coop floor bedding material (which included poop) into the nests. Some people like to put the nests higher so it is easier to look inside then for eggs, especially if they have a bad back. Or somewhere in between. Chickens don't care but as you can see some people care a lot.
The suggested minimum size for nests is 12" x 12" x 12". That should work well for your breeds. My chickens are sized similar to yours. I made my nests 16" x 16" x 16". That fit my stud spacing and if you cut a 4 feet long piece into 16" lengths there is no waste. There is no waste at 12" lengths either.
I have two rows of two nests stacked. That takes up less wall space than a single row of four nests. The hens use all of them. Most hens lay in the same nest but that popular nest will sometimes switch around. I've had broody hens hatch in low nests and high nests.
Next I position the roosts. Chickens usually like to roost on the highest spot available and I do not want them sleeping in the nests so my roosts are higher. My droppings board is about 6" higher than the top of the nests. The roosts are several inches higher than that. I use a garden hoe with a shortened handle to scrape the roosts so I have enough room for that between the droppings board and the bottom of the roosts.
Chickens can be hard to catch during the day but at night you can pick them off of the roosts. I'd want the roosts a convenient height for that. I'm basically looking at higher than anything you do not want them sleeping on but as low as reasonable.
In Upstate New York you will have cold winters. They need decent ventilation to get rid of excess moisture from their breathing, poop, and drinking water. Youi don't want a cold wind hitting them on the roosts so your open ventilation needs to be higher than the chickens when they are roosting. I like some openings as high as I can get them, that helps air circulation.
I only have one window in the north end of my 8' x 12' coop. But I have ventilation all around the top, open space on all sides covered with hardware cloth for predator protection. That lets in a lot of light.
Now to your questions. Horizontal layout for 12 full-sized fowl hens. What you have should work well. You need room for you to be able to move in there and work. I'd want the roosts far from the human door so they are more out of the way. Your hot walls from the sun are going to be the south and west so I'd want your nests and roosts on the north and east sides. Other layouts could work but I don't see anything wrong with yours.
Chickens like to roost at the highest spots available. The ones highest in the pecking order sleep where they want to and push the others out so those settle for what is left. Whether your roosts are ladder style with some higher than the others or they are all the same height they are going to squabble over them. Either style can work well. Dad's were staggered, mine are the same height. Chickens used both styles.
My Australorp, Sussex, Delaware, Rock, and Orpington have no problems flying up to a roost five feet above the coop floor. They have no problems flying down in the morning. They don't hurt themselves. Mine do have a clear landing space in front of the roosts but I've had some fly forward from the roosts about 8 feet, hang a 90 degree turn to the left, fly out of the human door, and land in the run. I even had a grown full-sized rooster do that once, almost hit me as I was going in the door. Mine are hatchery quality chickens, not the show chickens that are bred to grow big and are fed to grow big. Maybe that makes a difference.
. 12" overhangs with open soffits, a roof peak vent, and large gable end vents.
