Aftermarket vent for small coop

[Cobber]

My wife and I inherited a small commercial coop with our three bantams.
It does not have any vents, although a different version has eave vents.
Another user indicated the coop needs vents. Is there an aftermarket product I could install, and would this be a problem in the winter (we’re in Indiana)?

 

[Ridgerunner]

It does not look like that is a ridge vent, just something to block the water. But it looks like the ceiling under it may have a gap at the top. My first thought would be to remove that angle on the top and replace it with a larger angle raised just enough to give you ventilation up there yet still keep water and predators out.

How high are the roosts in there? Can you put in a gable vent in either the back or front (or both) so they are still below any winds blowing through.

Your risk in Indiana in winter is that the humidity gets high in there so they are at a high risk of frostbite when it freezes. The humidity can come from their breathing, their poop, or any open water. If you have an opening up high that excess moisture can escape. You do not want a cold breeze hitting them on the roosts, that's why the winter opening needs to be higher than them on the roosts. With decent ventilation and wind protection they should be able to handle your winter temperatures.

 

[thecatumbrella]

Your risk in Indiana in winter is that the humidity gets high in there so they are at a high risk of frostbite when it freezes. The humidity can come from their breathing, their poop, or any open water. If you have an opening up high that excess moisture can escape.

Piggybacking off Ridgerunner's advice:

I have a small prefab coop with subpar ventilation (Omlet Eglu), and I recommend mixing some PDZ (also called zeolite) into whatever bedding you use and spot cleaning the coop daily. Hemp is very, very good at drying out droppings. It's a powerhouse combined with PDZ for removing ammonia and poo-based humidity.

 

[RoseHawke]

I haven't done this yet, but I also have a small prefab coop I'm going to add ventilation to. My intention is to use these 2-inch round soffit vents. I'm going to try installing them with a bead of silicone. For winter a quick 'n dirty would be to staple plastic over them, or build a frame to cover multiple vents, attach the plastic to the frame, then screws to attach the frame to the coop. If you wanted to get fancy, a couple of hinges and a latch on the frame instead of attaching it with screws.

 

[AmericanDwarfChicken]

I absolutely love your little flock! I started with 3 hens, two RIR and a Barred Rock! I lost one RIR to a hawk two years ago, but my Barred girl is 4 years old and still lays eggs daily! I’ve been thinking to shrink my flock to down less than 10, as having 30+ chickens can be a bit much at times.

 

[Cobber]

I absolutely love your little flock! I started with 3 hens, two RIR and a Barred Rock! I lost one RIR to a hawk two years ago, but my Barred girl is 4 years old and still lays eggs daily! I’ve been thinking to shrink my flock to down less than 10, as having 30+ chickens can be a bit much at times.

They're all grown up now and laying 1/day, although with the winter it's not quite as regular. We originally let them wander the yard, but started getting hawks stopping by for a peek. Our neighbors across the street free range in their yard and never get hawks. I have no idea how that works.
I found some vents to place in the eaves as high as I could get them. Also we clean out droppings daily. The run is enclosed now as well, but the chickens rarely hang out there unless its both windy and raining/snowing.