In some ways you can tell with the head. I have seen hens with a little red in the head but not much. However a gobblers head will change colors. Last year I was hunting and had a tom with some hens out about 150 yards. His head was bright red on the bottom and white on the top. All of a sudden he stopped strutting and almost instantly his head turned completely grey!!!!! When he took off running I saw 2 absolutely huge toms with the completely brightest red heads I've ever seen come running in and chase him off. It was awesome!!!! I wish I would have gotten a shot at one of those gobblers!!! Maybe this year.