What a wonderful way to teach children the months of the year, on a farm where every living thing is snug and secure. In January, it's a wonderful day to be a farm dog, pounding down a snowy lane and leaping through drifts. In brisk February, a warm light keeps fluffy chicks protected from draughts. No matter what the season, the animals adapt to the diverse weather conditions and thrive- -right through December, when the barn is a ``sturdy ship sailing on billows of snow.'' Luminous illustrations show the farm and outbuildings from various perspectives; Mathis lights up tree boughs to show the blossoms of May and a bluebird family, and bathes pink pigs, anxious to roll in the mud of rainy April, in a radiant glow. Month by month, Lesser and Mathis create an exuberant paean to life. (Picture book. 3-7)