My 12 week old barred rock girls will not go into their coop at night unless the light is on inside their coop. They have been outside for several weeks but because of chilly nights here in Vermont, they have had their brooding lamp on inside. But the weather is warm now. They have no problem finding home at night as long as the light is on, otherwise I find them all sitting on top of the fence or even on their own roof(even on very warm nights)!! Help! Did I spoil my girls or can I fix this? I don't want to keep the light if the weather doesn't require it!