My extra chicks go to snakes, but it's not information I throw around on a site such as this because I know it could irk a lot of people. I couldn't imagine volunteering that information face to face with someone I know loves chickens . . . I wouldn't say she's an idiot, but certainly thoughtless. I tend to think she may have thought of it as a sort of common ground y'all share and could talk about. Some people just have the knack of never saying the right thing.
To those asking why not just feed it rats . . . rats are extremely expensive, depending on whether you're buying live or frozen it can be five to ten times more expensive, and many reptile owners turn to poultry as an alternative. The snakes do well on them. I don't see the difference between using the bird as food while a chick vs waiting for it to grow up before slaughter, and you did say you sell chicks for eggs and meat . . . well, that's meat. Look at it in that light and you should feel better.
I will add that I never, EVER feed a live chick to a snake, making sure to humanely dispatch them beforehand. It hurts every time because I love chickens, but I feel much better feeding the bodies to my other beloved pets rather than wastefully disposing of them.