Boss is a good "treat" especially during the molt. But as you know, it needs to be on a limited basis. I think we both agree that poultry owners can be very harmful to their "pets" by over feeding "treats".Some of the young toms we butchered we internally greasy, than I had a hen prolapse, which is often caused by internal fat. Since I have cut back on the boss they are a bit healthier I think. You can't necessarily tell if stuffs going on internally until you get a look inside, or lose birds.
https://articles.extension.org/pages/69042/synthetic-methionine-and-organic-poultry-diets