I just watched this episode on the first season DVD with commentary by Garry Marshall & Jerry Belson, and in case anyone's interested, Gary mentioned that they got rid of the Pigeon sisters after the first season because ABC thought it would be better if Felix and Oscar could be seen going out with different girls sometimes.

For whatever that's worth!:)

That was probably a good decision, the "coocoo" Pidgeon sisters were really "one joke" characters, which was fine for the play, or the movie, but doesnt work that well on a weekly TV show.

yea; I've always though that.