Help with chicken with runny nose

[phate008]

This is the shed I have. https://www.amazon.com/dp/B0015MH7WQ/?tag=backy-20

Do you think that those small circular vents shown on the right side of the picture are sufficient venting? I wonder if I should install and exhaust fan up there to remove stagnant air, debris, or condensation.

 

[ChickenCanoe]

Insufficient. Compare those little holes with the ventilation in the following link.
http://www.nortoncreekpress.com/wordpress/poultry/fresh_air_poultry_houses_a/
http://www.plamondon.com/wp/cold-and-snow-vs-open-chicken-housing-wh/

A fan could work with what you have but it would have to be strong enough to move a fair amount of air. There are two types of forced air ventilation. One that is often used as you suggest is negative pressure (exhausting air to the outside). The other and less often used but what I prefer and that is positive pressure ventilation. I like the effect of pushing fresh air directly into the building.
The reason commercial poultry houses don't use it is the fear of introducing disease but if you don't have a lot of poultry houses around you that shouldn't be a concern.