What percentage of the US poultry market is sold directly to consumers
in grocery stores and supermarkets, versus restaurants, food
processors, etc?

I'll guess 25%. Some what less if you count the processing done in the
deli section of many super markets as indirect. Even less if you count
the essentially unprocessed chicken in syrafoam trays with shrink
wrap. Does it matter is the cutting and wrapping is done behind the
meat counter or at a different location, perhaps fully owned by the
supermarket chain? It may temporarilly jump to 30% the week before
thanksgiving as most of the turkeys sold have miminal processing. I'm
unsure if miminal counts as direct or indirect. If indirect then it
may fall to 10% the week before thanks giving as I suspect few meat
departments do even miminal processining of turkeys. Less than 1%,
year around, if poultry direct means they are slaghterd in the same
building that they are retailed.    Neil