Your coop is adequate. Everything we are telling you are just improvements that we feel are best. You know about prefab coops, and have already done much better for your flock!
The roof should be taller to keep the air from ventilation off their heads, and you didn’t mention roosts. Will they be miserable without roosts? Not necessarily, but if you can build that addition, a 2x4 laid flat about two feet up is probably best.
I am reminded about sand. Playground sand catches the poo, and you can rake/scoop it daily. It’s also a great dust bath year round!
The roof should be taller to keep the air from ventilation off their heads, and you didn’t mention roosts. Will they be miserable without roosts? Not necessarily, but if you can build that addition, a 2x4 laid flat about two feet up is probably best.
I am reminded about sand. Playground sand catches the poo, and you can rake/scoop it daily. It’s also a great dust bath year round!