I was quite surprised to hear that her calf was bigger than mine. She is a tiny girl (her mom can't be much more then 5'2-4"), who just happens to have some stacked calves.
I did look around the MH website, and saw that they do have some wide calf boots, but they are all regular height.
Is there any other brand someone could recommend that possibly has a short-wide winter boot? She will be riding in an unheated barn, in the middle of a Canadian winter, so it will be pretty cold.
The girl is a teenager with a 9-10 foot size, otherwise I would have suggested trying a youth boot....but then the calf wouldn't be wide enough anyways.