PreS-K In a box inside a shed is a nest on which there sits a little red hen. Proudly and patiently, she sits on her six brown eggs while the fancy white leghorns fuss around her. ``Took, took,'' she replies. Finally, after carefully primping and preening, she stands to reveal her six yellow chicks. ``Cheep, cheep!'' The three white leghorns proclaim, ``Took, took, took. . .!'' and the rooster crows, ``Cock-a-doodle-do!'' And the little red hen is the star of the barnyard. Fancy that! Although Fancy That! initially sounds like one of Allen's cumulative tales, it lacks the chain-of-events momentum and rollicking rhythms of Bertie and the Bear (1984) and A Lion in the Night (1986, both Putnam). The sole source of drama here is the little hen's secret. However, the book's graphic clarity and the simplest of plots make it a natural choice for toddlers, especially when one considers their fascination with animal young and animal sounds. Executed in Allen's signature style, the colorful line and wash illustrations are just the right size for group presentations. Simple lavender borders surround both the illustrations and the text but cannot contain the tooking, cheeping, and cock-a-doodle-doing of the farmyard fowl as they celebrate the new arrivals. Jeanne Marie Clancy, Wolfsohn Memorial Library, King of Prussia, Pa.