Love Donkeys
Crowing
I'm with you on walk-in coops! I broke my hip 9/11/2023. I can handle steps but hands and knees is another story.So... I will never understand why builders build such BEAUTIFUL coops, but do not offer functionality. Some will even fight you on doing/adding in that functionality - it adds time to the build, reducing (somewhat) their profit.
Things I would do -
1 - turn non-working cupola to a working one OR eliminate it to lower cost so can make other changes which will add back to cost.
2 - extend the 3 roof edges not attached directly to run. This allows soffit to be opened up for unseen ventilation. It also protects ventilation that may be added, up high, under the roof. Extend more than a foot (I'm not sure how much is needed) on nest box side so it protects the eggs & collector in bad weather (rain, snow, somewhat for wind).
3 - at least add a large ventilation area at the top of coop (full width - up to 3-4 boards depending on number of chickens) where the run joins the coop. The run will need to be roofed at least partially to protect that ventilated area. With a snow load you'd want at least partial run roof coverage - to encourage your girls to go outside.
4 - if you want the extra run space under neath, have it raised higher like Ted Brown's. Makes it easier to access that space.
5 - have a hinged wire door, big enough for your body to partially or fully fit under the raised coop. It could be hinged to raise up or to open out. Could even do a fully removable panel. This will allow you to reach eggs, sick or injured birds, change out feed and water if under the coop or clean out/add litter. Even to plant some plants if desired - helpful/liked by chickens & to deter pests/vermin. (https://www.backyardchickens.com/th...icken-run-a-mini-forest-for-chickens.1540569/).
6 - i would put this on some type of foundation, to protect the wood base.
Can be solid pavers, bricks, cinder block or poured cement to match width of base.
7 - instead of the FRP flooring, you could check into Black Jack 57 (i think). It is black. You paint it on the floor & up the walls - 1 - 2'. It protects the wood, i would think it helps in preventing pests & rodents, less slippery than the FRP. Possibly lower cost but not positive. Your builder may be able to do it, or you do it after coop delivered. (Article 'Black Jack Rubr-Coat #57, For Your Coop Floor.' https://www.backyardchickens.com/articles/black-jack-rubr-coat-57-for-your-coop-floor.75145/)
I think that's all. I might come back and add some thoughts.
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Have you considered a Woods styled coop? Would your builder be able to do something like that?
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I, myself, prefer a "to the ground", walk in coop. I am older & this past year dealing w/ a broken/dislocated ankle & full leg length blood clot (blood clots not fun - mostly spent 6 months on blood thinner w/ leg raised above heart to be effective. Any bump causing bruising could have meant internal bleed out before EMS could arrive. 2024 was a NOT FUN, lost kinda year), having a raised coop would be difficult for me. Whether it was one with stairs or one you reach into/under for servicing... Stairs & getting down on hands/knees still a BIG issue.