The aim of the experiments was to explain the high number of worms found in chickens from a poultry facility. Infections by Raillietina laticanalis were achieved in chickens kept in the laboratory. Thirty cysticercoids obtained from beetles (Dermestes ater) caught at the poultry facility were administered by pipette to each chicken. The rate of recovered worms was employed to evaluate the persistence of the infection, the influence of bird age on susceptibility to infection, and the possibility of reinfection. To verify the persistence of the infection, a group of ten chickens was infected. At each of five different intervals, two chickens were necropsied. Tapeworms were recovered up to the 46th day. To verify the influence of bird age on susceptibility to infection, three different age groups were used in the experimental design: 3-4 weeks, 6-9 weeks, and 17-20 weeks. There was no difference in susceptibility to the infections across the groups. To investigate the possibility of reinfection, a group of birds received an additional dose of cysticercoids a few days after the first doses. Another group received the second dose only after the worms had already been established. There was a significant increase in the number of recovered worms in both groups when compared with the control. The short worms found in some experiments may be due to natural destrobilisation. Thus, the high number of worms found in chickens from the poultry facility could result from both infections being acquired earlier and infections acquired at the laying stage, since we demonstrated the possibility of reinfection and the long lifespan of the worm. If destrobilisation occurs in the same manner in chickens from the poultry facility, the longer worms found in them must be younger than the short ones. © 1994.521-2157162Ackert, Reid, Age resistance of chickens to the cestoda Raillietina cesticillus (Molin) (1937) J. Parasitol. Suppl., 23 (6), p. 558Avancini, Ueta, Manure breeding insects (Diptera and Coleoptera) responsible for cestoidosis in caged layer hens (1990) Journal of Applied Entomology, 110, pp. 307-312Coutts, (1981) Poultry Diseases under Modern Management, p. 245. , Saiga, Hindhead, Surrey, UKGray, Studies on the course of infection of the poultry cestode Raillietina cesticillus (Molin, 1858) in the definitive host (1972) Parasitology, 65, pp. 243-250Krull, (1969) Notes in Veterinary Parasitology, p. 599. , University Press Kansas, Manhattan, KSRead, The role of carbohydrates in the biology of cestodes. VIII. Some conclusions and hypotheses (1959) Exp. Parasitol., 8, pp. 365-382Skutar, The life-cycle of Raillietina (Skrjabinia) fedjuschina Skutar, 1963, a parasite of domestic fowl (1963) Dokl. Akad. Nauk SSSR, 151, pp. 1474-1475Vijayakumaran Nair, Nakadal, Haematological changes in domestic fowl experimentally infested with the cestode Raillietina tetragona (Molin, 1858) (1981) Vet. Parasitol., 8 (1), pp. 49-58Wehr, Cestodes (1972) Diseases of Poultry, pp. 884-910. , M.S. Hofstad, H.J. Barnes, B.W. Calnek, W.M. Reid, H.W. Yoder, Iowa State University Press, Ames