For the second time this season, Elinor Donahue does not appear. Betty, her character, it's explained is at a friend's studying for a test.
An unusual filming tactic was used in this episode. At the end of the program, Margaret Anderson (Jane Wyatt) turns directly to the camera and says, "This was one of the 'bad' days." She is speaking directly to the television viewing audience. In "theater language," she has "broken" the "fourth wall," which is the space which separates a performer from an audience.
Throughout the series, Billy Gray frequently demonstrated his prowess with acrobatic stunts: e.g. cartwheels, vaulting over the lower half of the kitchen dutch door. Here you see him employ a nip-up maneuver to thrust himself into a standing position from a supine position on the floor.
Words uttered by the little girl here found their way into The Taxman Cometh (1996). That production would swipe jokes from many other sitcoms (most notably from Ellen and Who's the Boss, and to a lesser degree from Wings, It's a Living etc.) and pass them as their own, without credit whatsoever. Here, it has to do with chinchillas, which the little girl says she raises. There, Fran tells the taxman that she raises chinchillas and that's her dependents.