Influence of exposure period and management methods on the effectiveness of chickens as predators of ticks infesting cattle.

Experiments undertaken on Rusinga Island, Kenya, indicated that Rhipicephalus appendiculatus (Neumann) was the predominant tick consumed on tick-infested cattle by chickens, followed by Amblyomma variegatum (Fabricius), Boophilus decoloratus (Koch) and Rhipicephalus evertsi evertsi (Neumann). The number of ticks consumed by chickens released with cattle in a 3 h release period was not significantly different from ticks consumed in a 4 h release period. In a free management system, chickens 1-3 months of age consumed more ticks than older ones; in a confined management system however, chickens 4-6 months of age consumed more ticks than younger birds. Although the numbers of ticks consumed by local and exotic breeds of chickens were not significantly different, a period of 8-10 weeks was necessary for the exotic breeds to become behaviorally adapted to tick predation on cattle. Local chickens bred in environments where cattle were absent took a shorter period of 4-6 weeks to adapt. It was concluded that the relatively large number of ticks consumed by each chicken during the 3 or 4 h release period is an indication that a good reduction of ticks on cattle can be achieved through tick predation by chickens. The preponderance of R. appendiculatus over other tick species consumed was a reflection of its relative abundance on cattle on the island rather than a selective preference for tick species.