OK, "buzzards" are the same as "vultures". Which are carrion eaters. They wait until Whatever-It-Is is safely dead, THEN they eat it. That's why they have no feathers on the head and neck: so they can eat dead carrion without too much blood/yikes sticking to them and that keeps them cleaner.
We have a lot of them here and I've spent years observing them because I just freaking love birds - any birds. What I have observed is they are terrified of anything that can still move, and they are incredibly cautious even with things freshly dead.
Remember this little ditty: Correlation does not equal Causation. Seeing a coyote right after you see a full moon does not mean that coyotes cause full moons. Just because you see vultures, that does not mean that vultures carried off your chickens. The most likely suspect, actually, is a domestic dog. Or a fox. Flying off with two pullets is really pretty tricky: Turkey Vultures weigh, at the most, 4.5 pounds. How much did your two pullets weigh? Now imagine weighting a commercial airplane with MORE than it weighs. You think it will be able to get off the ground? In actual fact, in order for that plane, or that bird, to get off the ground and fly, they can't be carrying even their own weight in freight. Turkey Vultures and other raptors generally eat on the ground. That's because it is IMPOSSIBLE for them to fly off with their prey.
Check the ground and surrounding area for tracks. That is more likely to identify the culprit.