Passive integrated transponder (PIT) tags have been used to mark a variety
of organisms and have potential for marking poultry chicks. We examined the
effects of PIT tags subcutaneously implanted in 3- and 7-d-old Leghorn chi
cks and found no significant differences over 40 d in survival or rate of d
aily body mass gain among tagged chicks and controls. The PIT-tagged birds
were not more susceptible to pecking by other chicks than controls. No bird
s died, but 1 of 20 chicks lost its tag during the study. We believe that P
IT tags provide a viable technique for marking individual juvenile birds, i
f tag loss can be reduced. Costs may be prohibitive in studies involving la
rge numbers of birds.