Wiktionary
hen-witted
a. foolish; birdbrained.
Usage examples of "hen-witted".
One glance at the radiant vision on the threshold was enough to inform her that Hester, like the hen-witted female Lady Widmore had for long considered her to be, had lent one of her own gowns to the interloper.
Good God, Serena, you can’t have supposed that I wanted to marry that hen-witted girl?