Allow food to be sent with armies to reduce troop losses by 1% for every 10 food sent per troop. Healthier troops die less.
Lets people use up stockpiles and makes it worth Shepherds running more than 2% Farms.
Make it so you must send at least 1 bushel per troop, or suffer 10% increased losses. Makes starving a province much more potent and again food more useful.