have kangaroos in your top paddock
have kangaroos in (one's)/the top paddock
To act, think, or behave in an eccentric, foolish, or nonsensical manner; to be insane. Primarily heard in Australia. Tommy must have kangaroos in the top paddock if he thinks he can convince Mom to let him get a tattoo for his birthday. There's an old lady who stands on the corner yelling at strangers all day. I think she might have kangaroos in her top paddock.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
have kangaroos in your top paddockor
have kangaroos in the top paddockAUSTRALIAN, INFORMAL
If you say that someone has kangaroos in their top paddock or has kangaroos in the top paddock, you mean that they have strange ideas or are crazy. Some people think I must have a few kangaroos in the top paddock. Note: Roos can be used instead of kangaroos. A guy who pretends to understand women has got roos in his top paddock. Compare with have bats in the belfry. Note: A paddock is a small field next to a farm or stable. The idea is of having wild animals there instead of farm animals.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012