If the lady was older she probably learned it way back when like I did. Thing is there are so many better alternatives now. Back when I was a teen a horse was pretty well done at 20. Now it's not unusual to find them still working in their mid 30's. And you even hear about an odd one here and there making it to 50.
Maybe you can swap the sweet feed for some hay with somebody. Or mix the two feeds so you change the baby over slowly.