http://www.syndicatelofts.com/gerard-and-bas-verkerk-different-location-same-top-performances-part-2-of-4/ For 10 years the family Verkerk have been darkening the old pigeons (cocks and hens). In 2012… from early March until the end of April… and from 6 pm until 8 am the lofts were in semi-darkness. From the end of July they got extra light… from 5 am until 10 pm it was light in the lofts. They use ordinary energy saving bulbs… and not bulbs with nitrogen, as sometimes is suggested. After the last race, the lights are turned off… and at basketing for that last race, most pigeons have cast 4 to 5 flights. Because of the extra light, the flight feathers are changed usually… but the wing coverts are not cast.