Widow hen not only breaks the fourth wall, she addresses Foghorn by his proper name, Mr. Leghorn.
The title plays on the nursery rhyme 'Little Boy Blue'.
Junior chemistry sets, popular at the time, were not exactly harmless. They contained real chemicals. Modern versions are no longer dangerous.
Junior is portrayed as a scientific child savant. The book he is shown reading, Splitting the Fourth Dimension, usually referred to the concept of linear time in the space time continuum, a popular theme in science fiction of the era.
The curious looking object Junior uses in his calculations is an old fashioned slide rule. Although now considered archaic, some are still in use today (2022) by old school scholars and modern hipsters.