Unless your state has a law requiring a certain amount of knowledge to employees, and I sincerely doubt your state has one, this is legal. I'm not going to say it's good management because it isn't, but it is legal.
The cost of healthcare is skyrocketing and many companies, particularly small companies, are finding that unless they reduce benefits, increase employee costs, or both, they will no longer be able to afford to provide health care benefits at all.
By the way, if I had a quarter for every time an employee complained to me that they were not notified of something, only to have me pull out the memo I circulated that they never read or show them the e-mail in my "Sent" file that they deleted unopened, I'd be able to take a trip to Hawaii.