I'm sure like everyone else you hate to call the vet for every problem, but in your situation I think it wouldn't be a bad idea to just talk to a vet. See if they can give you some insight. It is hard for anyone of us to understand your situation when we cannot be at your facility and see the heifer, her housing, her feed, the weather, and many other things that could factor into the equation. It is always better to be safe than sorry. Best of luck with her and let us know what you find out.