【mad as a March hare】 —crazy; insane:

• Anyone who thinks the moon is made of green cheese is 【mad as a March hare】 .

【mad as a wet hen】 —(also: mad as a hornet) very angry; extremely irritated:

• Mrs. Harris was 【mad as a wet hen】 when the rabbits ate all her tulips.

Note: Neither expression fully correlates in meaning with the phrase mad as a cut snake—(Austral.)

1. = 【mad as a wet hen】 :

• I was as mad as a cut snake to hear that the telescope was going to be left to die, and it’s good to see that the administrators at NASA have changed their minds.

2. = mad as a March hare:

• Many people I’m sure thought Geoff was as mad as a cut snake, and it’s true, he did occasionally appear to have a tenuous grip on reality.