madder than a wet hen

Madder than a wet hen is an idiom used when someone wants to describe how upset someone is. Madder or to be mad can be used in a variety of different uses such as being upset or angry, or acting crazy and slightly off-kilter. Hens when they get dumped in water to be cleaned get very upset about this, and also act a big crazy, so being madder than a wet hen can work in both instances.