Welcome to BYC. Where, in general, are you? Climate matters, especially when it comes to housing.
I'm afraid that I see several problems in those photos.
First, chickens fly at about a 45-degree angle. There doesn't appear to be enough room for them to fly up to the roosts and to safely fly down rather than just falling.
Second, that ladder is VERY steep. It's usually recommended that chickens' ramps be no steeper than about 30 degrees.
Third, I see no ventilation at the upper level. Heat and ammonia both rise so the higher levels of the coop are probably hot and stuffy.
Here is my article on coop ventilation:
https://www.backyardchickens.com/articles/repecka-illustrates-coop-ventilation.77659/
And some basic information about chickens' space needs:
The Usual Guidelines
For each adult, standard-sized hen you need:
- 4 square feet in the coop (.37 square meters)
- 10 square feet in the run (.93 square meters),
- 1 linear foot of roost (.3 meters),
- 1/4 of a nest box,
- And 1 square foot (.09 square meters) of permanent, 24/7/365 ventilation, preferably located over the birds' heads when they're sitting on the roost.
20 hens
- 80 square feet in the coop. 8'x10' is the most practical because 7'x12' or 6'x14' require a lot of weird cuts.
- 20 feet of roost
- 200 square feet in the run. 10'x20', 12'x16' or 8'x25' as suits the land available.
- 20 square feet of ventilation.
- 5 nest boxes.
Roosters are usually larger and take up some extra space each.
Not roosting isn't harmful per se, but as they get bigger they'll drop increasing levels of poop that they're sitting in all night.