Remove the light. Your birds need this time of year to acclimate to the coming colder weather. Their feathers will thicken up and they will gradually get used to cooler temperatures.
Keeping them artificially heated will cause them to not be able to handle the winter temperatures, and can cause them to be more prone to illness.
Keeping them artificially heated will cause them to not be able to handle the winter temperatures, and can cause them to be more prone to illness.