can a company force you to use vacation days if they are going to be closed?

My husbands company let them know that they will be closed for a week in July and a week in December. They also advised that during this time the employees will be required to use their vacation time and if they don't or don't have any left they will be wrote up. Can they do this????? If the company wasn't shutting down these two weeks none of the employees would miss work. How can they force them to use their vacation days when it's the companies mandatory shut down