What is the correct way to avoid light from racing pigeons

The pigeons must be available to pigeons and put less pigeons, which can promote it to change feathers without led to gaining weight.If you want to avoid light, you must first prepare a shed. The ventilation of the shed is better, otherwise it will cause pigeons to lose hair and even make them sick.Secondly, you must prepare a grain ratio, what materials are used for retreat, and what materials are used for long hair.Usually at 8 o'clock in the morning, and avoiding the shed at five in the afternoon to control the light time.