Hens are adult female chickens. In this context, "brooding sorts" refers to hens that exhibit brooding behavior, which means they are prone to sitting on their eggs to keep them warm and incubate them until they hatch.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: University of Delaware's Fightin' Blue ___. Explanations are generated by AI and may be inaccurate.