A ""rollicking adaptation of a traditional folk song,"" we're advised--about a farming couple who change places for a day, cope variously with each other's accustomed tasks, and conclude, amicably, that ""they'd have more time to play/ If they could work as one."" The ending is something of a surprise, except insofar as it reflects today's new-born penchant for amity between the sexes and marital accord. But the story, as pictured, is a broadly-drawn, rather grim burlesque: the husband and wife are bears, the illustrations are done in heavy, large-scale linoleum cuts, crudely colored in shades of orange and black. Whatever levity there might be in the tale is lost in the ponderous look of things.