I need help with building my chicken coop

The vent I am talking about is at the top of the coop and stays open all year round to let air in, even in the winter. There are windows on three of the walls that can open in the summer and then can close in the winter. I checked out a book from the library today that showed an open vent that was 5" That really helped. I can stare at a tape measure but cannot always get the distance in my head of how it would look on a finished coop.

In the picture I posted he had a board in the top with holes cut into it. But I think just having it open would be better and more ventilation.

Sorry for all the questions. There is so much info out there that it gets confusing. And some of them just do not seem to have direct answers. Such as the ventilation. Everyone agrees there should be a lot of ventilation but no one says how much "a lot" is.

From what I read there needs to be 12 inches head room between the roost and the top of the coop. So would 18 inches under an open vent area be enough for them not to get a draft in the winter? I know the air flows along the top and out the other side, just want to make sure it is not blowing on the chickens as it goes across.

So what h are meaning is like something likes gable vent on each end and I would imagine that 18 inches should be good so they don't get a draft

18 inches from the roost to the ventilation should be good. It will give them plenty of headroom. Here's one way to do ventilation

Here is another. You could do this all the way around the top of your coop. is this what you mean that you don't want to cut holes in the boards? I think I personally am going to do this actually but everybody does what they like and what works for them.

The top pic is what mine looks like just mine is tighter so nothing can get in so I don't need the hardware cloth or anything and those things are like two feet long and about 2 inches tall so they let in a lot of ventilation

Yes Leigti, that is what I meant.

Roada Red, yours are less than 2" ?

I was planing on doing mine 5" and then the length of the coop so 4 feet, Is that to much ventilation? And Leigti, you think I should do all the way around? I thought that would cause a draft... ?

Thank you guys so much for answering. I really appreciate it.

Mine are two inches from the roof and the wall inside and then those gaps are 2 feet long but only down the sides so that's 8 feet on each long wall not the two 4 foot end wall I wouldn't do it the whole way around I don't know if it will cause draft though