How many people will a guinea fowl feed?

Eight people, would be one good answer, but not very instructive.

The answer lies in how hungry your guests are, of course, but let's break it down.

A whole chicken is usually cut up into these pieces:

Two breasts (white meat)

Two wings (dark meat)

Two drumsticks (dark meat)

and two thighs (dark meat)

So eight pieces and a carcass or back.

So your eight guests could each get a piece of chicken assuming they were not too picky about the piece they ate. And the real hungry guy could get the back too.

Personally, I'd take half a breast and the carcass and make chicken soup and have another whole meal for everybody.