Exemined 942 fecal samples of garden - range chicken in Thai Nguyen city, the results who wed that: The infectious rate of tapeworm was 35.56 percent, varied from 29.54 percent to 44.55 percent. The slight infectious rate was 71.94 percent, the median infectious rate was 20.30 percent, and serious infectious rate was 7.76 percent. Autopsy of 115 chickens, the infectious rate of tapeworm was 36.52 percent, varied from 26.67 percent to 43.75 percent
the infectious intensity from 3 to 109 tapeworms per chicken. The infectious rate was highest in chicken of 6 months age (60.20 percent by examined feces and 52.00 percent by surgery), that was lowest in chicken under 3 months age (20.90 percent by examined feces and 26.92 percent by surgery). There are 5 species of of tapeworm in scavenged chicken in 4 communes of Thai Nguyen city, they were: R. tetragona, R. echinobothrida, R. cesticil/us, R. volzi, Cotugina digonopora (the frequency to appear them was from 50,00 percent to 100 percent).