fool hen

This is another of the grouse family that has been given the name of "fool hen," on account of its naturally tame nature.

While we were unloading the horses, a "fool hen" came and lit in a tree near us.

I suppose you didn't notice if you hit that fool-hen, Colonel Cruickshank?

If a poor cackling grouse or "fool-hen" be thrust into the pit, the Indian is almost sure to find a prisoner.

I guess that's why it's called the fool hen, though its proper name is the willow grouse.