Antique (ok, older than I am!) scale found amongst Grandfather's barn before he sold the farm.
A large size Rubbermaid tub (clear, so I can see what they're up to!) with no lid, but high sides so they aren't apt to leap out immediately - the tub is bungie corded to the scale so it won't flip. Weighs up to 25#'s - thankfully, haven't had to go that high with chickens!
I like this one because I can calibrate it (so the weight of the Rubbermaid tub is not part of the equation). And yes, I've tested for accuracy, it's very consistent.