A tunnel-ventilated pullet house with light traps is one of the most difficult types of poultry houses to design a ventilation system for. There are dozens of different types of light traps to choose from, each with differing abilities to reduce the amount of light entering the house. How much each of these light traps restrict air flow also varies widely and does not necessarily correspond with their “darkness”. As a result, some light traps are very dark as well as restrictive. Others are ...not very dark yet are very easy to pull air through. Still others are both very dark and are very easy to pull air through.