Thank you, that is dang near exact to what I'm thinking. Only 4 ft to about 3.5 ft on the slope.
Since plywood comes in 4 x 8 sheets there's less cutting involved if you use them for the sides, then just add a little height onto the back and put hardware cloth there and make the slope.
Just a suggestion but it is an easy way to get some ventilation.
it will be well below the heads of the chickens when they're on the roost. This allows good ventilation. The winters get cold here too but I'm not worried about the cold. Heat kills much quicker than cold. So I built the coop on the shady side of the garage.