One of many marvelous references to "crazy." Quite a few such descriptions spring from vintage homemaking or housekeeping terminology --consider also "She came right off the spool" and "He's missing a few buttons off his shirt." Obviously pioneer women were just as capable of coining colorful colloquialisms as were the men.

He's got a big hole in his screen door.

She's a couple sandwiches shy of a picnic.

The porch light's on but no one's home.

Her phone's off the hook.

He lost too many balls in the high weeds.

He's overdrawn at the memory bank.