Waitrose sell this under their own label but it’s available widely and has been for years. The name isn’t a bad attempted pun, but refers to the way that chickens in the vineyards like to eat any fallen grapes. We feed our chickens any over-ripe grapes, strawberries etc, so I can believe this. Picpoul is an old variety and is also used in the manufacture of Noilly Prat vermouth. It is also grown in the Rhone valley and can be added to Chateauneuf-du-Pape, and in the Loire valley is known as Gros Plant.