so I live in Las Vegas Nevada this year is very warm here but this issue has been going on for a while my chickens do not go in when the Sun Goes Down during summer time I'm chasing them in about 10 o'clock at night during the winter time about 8 p.m. At night I am NOT concerned and this question has nothing to do with predators my question is because my chickens are not following the season and how many minimal winter hours and sleeping will this shorten their life or have any of it ill effect on their health