The best time for me to observe is in the morning, I spread their scratch out in a loooong line so there's a place for everyone.^ this is similar to one reason I wish mine was visible from the house. I really like watching them, and I'll sit out with a folding chair in spring-fall. But when the weather is bad or is cold out I feel rather neglectful because I don't spend much time with them other than feeding and watering. Spending even just five or ten minutes in the day where I sit and watch lets me know early if anyone is acting different, sick, or injured.
Then I open the pop door and watch them come out and feed, can see then if anyone is hanging back of having trouble moving.
I do this all year around unless weather is just atrocious.