Barack Obama -- Turkey Pardoned by Prez Has Been KILLED!!!

It's a Thanksgiving conspiracy -- one of the turkeys pardoned by President Barack Obama last year was euthanized this week ... just days before Turkey Day ... and so far, no one's saying why.

A rep for the Mt. Vernon Estate -- where the pardoned turkeys are SUPPOSED to live out the remainder of their days in pastured leisure -- said the turkey (named Peace) was euthanized Monday following an illness over the weekend.

But the rep didn't know what kind of illness it was, how it was subsequently killed, or what the plans were for the turkey's delicious remains.

The rep says the decision to exterminate the fowl was made by a local veterinarian.

Coincidentally, the Mt. Vernon Estate DOES serve turkey on Thanksgiving.