Measurements of usefulness
Useful as:
- tits on a boar hog
- a rubber crutch

These expressions were current about the same time as facetious questions posed in response to a self-evident statement or question. For instance, if someone asked you if you would like to make $1000 for 10 minutes easy work, you might respond:

Is a bean green?
Is the Pope catholic?
Does a bear shit in the woods?

and, later addition,
Does the Pope shit in the woods?

To reply in the negative,
Has a chicken got lips?