Teaching an old chicken a new trick

This is Miss Wattle. She's one of our old girls. She has spent the last several months molting and I am astounded by her new colors. She is beautiful! For comparison I have put a picture (the only good comparison I could find) from a couple years ago. You wouldn't think it was the same chicken. She was always a drab looking chicken. There are several ideas I have. One, she hated the rooster we had and would stay in the coop most of the time. He would chase her mercilessly if she was down. He is no longer and there is no stress from that quarter. Also, our girls are wandering out and about more so she is getting a more varied diet, exercise and more sunshine. Who knows... but I'm happy for her. None of the other birds have had a change like this...