At the time of this short, Jack La Lanne keep fit and the buff residents of Muscle Beach in Los Angeles were becoming part of the local culture. So Foghorn's calisthenics are not surprising to see.
Plymouth Rock chickens, mentioned by Henery Hawk as he drags off his prey, are an American breed that originated in Massachusetts.
Just after Foghorn Leghorn gets rid of Henery Hawk by putting him on a tray and then tossing the tray away like a Frisbee, Barnyard Dog sees the tray and calls it "A little man from Mars!", which originated from Orson Welles's radio program 16 years earlier.
Richard Thompson, who normally animated for the Chuck Jones unit, was a credited animator on this Robert McKimson short, the only instance of it.
Both Foghorn Leghorn and Henery Hawk appear, with names, in the opening credits.