Some light would definitely be helpful and without pictures, I doubt the chicken doors would be sufficient. The coop is an area that chickens will spend some time in during the day, at least during inclement weather, when colder and when laying eggs. Walk into the coop, close the main door and open the two chicken doors to get an idea of what it would be like.
There are multiple solutions for light:
- Windows- glass or swing open with hardware cloth (1/2" mesh) to keep out predators.
- Skylights.
- Electric lighting- wired or solar with timers.
At least as important is good ventilation. At night when they are all sleeping and even in winter, they need airflow to allow moisture to escape. Any vents/openings should be able to keep out predators. Again, hardware cloth is good for this.
Use hardware cloth instead of cheap chicken wire. The latter is good for keeping chickens in, but not keeping predators (raccoons, possums, etc) out as
this thread sadly proves.
Check out the
coops area to see plenty of examples that others have built. Since you are new to BYC and don't yet have chickens, I recommend plenty of reading and asking questions. Better to plan up front than jump in and make easily avoidable mistakes.