Even though the committee that picks degree recipients hasn't been selected, the possibility that President Reagan might get an honorary degree from Harvard University is stirring up campus debate. The president has been invited to Harvard's 350th anniversary in September 1986, but he has not yet responded . . .

Frank Perdue, 65, the chicken man whose television commercials have made his name and face famous, at least to the East Coast, has renounced bachelorhood. Last Saturday he married New York investment banker Kathleen M. Markey, 37, in Manhattan's Holy Trinity Episcopal Church. It was Perdue's second marriage and Markey's first . . .

Sometimes, if a jazz buff is truly lucky, the unexpected will happen. The most-recorded jazz pianist, Oscar Peterson, who is performing at Charlie's Georgetown this week, had a special treat for his fans Tuesday evening. One of the all-time great jazz drummers, Louis Belson, sat in for the entire second set. Belson, who is married to singer Pearl Bailey, had watched the first set and went to visit with Peterson in the dressing room after the performance. When Peterson returned for the second set, Belson replaced drummer Martin Drew for the remainder of the evening and the audience loved it . . .

Actor Stacy Keach, who has been serving a prison sentence in England for smuggling cocaine, announced yesterday he will marry Polish-born actress Malgosia Tomassi after he is released from prison next month. Keach is in the process of divorcing his wife, Jill Donohue . . .