After two airings CBS has decided to renew the new serial “Second Chances” through the rest of the season, ordering 13 additional episodes.Meanwhile, Fox Broadcasting Co. has cut its order on Disney’s “Bakersfield P.D.” from 22 to 17 episodes and will pull the series from its lineup later this month, with the remaining episodes to be held until June. “Monty,” another Disney comedy starring Henry Winkler, is expected to replace “P.D.” in January. “Bakersfield,” a half-hour filmed series starring Giancarlo Esposito and Ron Eldard, has drawn critical praise but weak numbers airing at 8:30 p.m. Tuesday, averaging a 4.4 rating, 7 share season-to-date in Nielsen. As a result, many observers were surprised when Fox, citing its quality, gave the show a back-nine-episode order. Through a spokesman, Disney exec VP Dean Valentine said, “We’re frustrated that a show of this quality has to struggle so hard to stay alive on network TV, ” adding that the studio was hopeful “P.D.” would gain “the attention that it deserves” in its summer run. As for “Chances,” the show’s two-hour opener drew a modest 9.7 rating, 16 share, followed by a 9.6/16 for its timeslot-premiere last week. Those numbers aren’t appreciably better than the previous aspirant to replace “Knots Landing” at 10 p.m. Thursday (“Angel Falls,” canceled after completing its six-episode order). But CBS apparently has more faith in “Chances,” said tobe among the network’s highest-testing series. The full-season pickup brings the total buy on “Second Chances” to 20 hours, including its two-hour premiere. The series is produced by former “Knots” and “Homefront” producers Lynn Marie Latham and Bernard Lechowick, who signed with ITC Entertainment to distribute the show. Connie Sellecca, Megan Follows and Jennifer Lopez head the ensemble cast.