Five little verses and the score for what is described here as an old camp song tell of six little ducks who ""started for market one fine day/ But lost their wares along the way"" . . . can't afford bread so they bake some instead, then eat, sing, dance and sleep until, next morning, one wakes the others with the repeated refrain, ""Quack Quack Quack."" Conover's busily furnished illustrations, alternately burnished color and black line, show the ducks at a teeming animal market and at home on a cozy house boat. Pleasantly domestic and agreeably rendered as they are, it's impossible to take them in all at once and just as unthinkable to hold up the song, which like all such ditties needs reeling through with a rapid bounce and a minimum of mulling over. But this is an established genre and if you can find a place for such practitioners as Robert Quackenbush you likely have room for these six.