For a WW2 tactical game I play (Men Under Fire) it's important to know whether a tank commander is spotting outside the turret cupola or is "hull-down" -- so to speak.
Many milk cartons these days in the US come with a plastic cap, under which is a safety seal -- a ring that pulls off a slightly concave cap (that looks a little like a shallow British Helmet Mk I). For the most part, my tank models have the commander exposed. When I need to mark him "down" I loop one of these seals -- suitably painted -- over the figure.
I like the idea of farm animals for designating unit status. Chickens for routed and sheep for shaken I can see, but pigs are very orderly and methodical. Wonder what I could use for WW2 in the Western Desert -- jerboas, gazelles and camels?
For Command Decision and Johnny Reb, I use the milk carton caps themselves -- suitably painted and with the unit designation on top -- to cover my order cubes (they used to be order chits but I glued the six most common order chits onto 1/2 inch [1.5 cm] wooden cubes).