In A Taste of History by Maggie Black (English Heritage 1993) meat cooked in a jug. She says this: “…poultry, game or small quantities of meat could be placed in an earthenware vessel with butter, herbs and spices, a lid sealed in place with a strip of pastry, and the vessel immersed in the cauldron for a few hours. In this way, richly flavoured and tender dishes were produced, including jugged hare, in which the jointed animal was cooked in a jug.”
Sounds fine to me.
Elisabeth Ayrton in The Cookery of England (Penguin Books 1974) a recipe for jugged hare is given which, as well as hare meat includes bacon, onions, carrots, herbs and spices, port, red wine and redcurrant jelly. Looks delicious! All I need is a cauldron and some hare meat.