In houses with clear curtains, getting the birds to spread-out evenly after turning out from half house for the most part is not very difficult. Just a couple of sunny days, with the resulting high light intensity in the house, and the chicks are running around and have soon evenly distributed themselves throughout the house. In a totally enclosed house or one with black curtains, the situation is much different. Even with the lights at full intensity, light levels are often 100 times lower than... what is experienced in the typical conventional clear curtain house. The lower light levels dramatically reduce bird activity which results in a significantly longer time for the birds to spread out. Many producers are on light restriction programs which both reduce the level of light and number of hours of light a day right around the time the birds are turned out into full house and these factors may slow down distribution even more. The challenge for producers is that if the birds are not evenly distributed by three to four weeks of age, they most likely never will be. This may adversely affect broiler performance and also heating costs.