Forced Vacation

Recently due to the downturn in the economy, our company has scheduled workers less time - from 40 to 35 hrs/wk. I am a benefits elligible worker of 39 yrs. with the company. I have to maintain 35 hrs/wk to maintain benefits. However, a supervisor is telling us that we must use our vacation time to suppliment our working hours to maintain the benefits- and has called us off our scheduled hours that morning due to a shortage of receiving shipments. Is this a violation in Missouri?

"Is this a violation in Missouri?"

No.  It is a consequence of the economy and is legal.  They can require you to use PTO/vacation to supplement the missing hours to maintain your benefits and pay.  You can elect to not use it and miss out but it isn't recommended.  If they are having this much trouble I would be burning through that vacation time and quietly looking for another position.