"As mad as a wet hen" is a well-known phrase to describe someone who is extremely angry or agitated. However, there are a variety of synonyms for this phrase that can be used to express similar emotions. Some alternatives include "furious," "irate," "enraged," "incensed," and "livid." These words can be used to describe someone who is boiling with emotions and cannot keep their temper in check. Other synonyms that might express a similar sentiment include "seething," "wrathful," "fuming," "exasperated," and "infuriated." Using these words can help writers create a vivid depiction of someone who is extremely angry or upset.