German idioms - and their genesis - 7

1. Einen Vogel haben

1. to be mad as a hatter

English below

Früher gab es die Vorstellung, dass Menschen, deren Verstand verwirrt war, Tiere im Kopf hatten, die dafür verantwortlich waren. Wenn sich jemand seltsam benahm, hat man gedacht, in seinem Kopf sei statt des Gehirns ein Vogelnest samt Brut..

There used to be an idea that people whose minds were confused had animals in their heads that were responsible. If someone behaved strangely, people thought that there was a bird's nest and brood in their head instead of the brain.

Die Alte hat doch 'en Vogel!