In altricial birds fledglings may be selected for visiting nests of non-biological parents when the rearing conditions in the nest of origin are poor or when they have difficulty in finding food just after being independent. When nest-switching is frequent and incurs fitness costs to the foster family, kin-recognition mechanisms may evolve to discriminate against foreign fledglings. Although nest-switching has been reported in several altricial birds, so far it has not been experimentally investigated whether nest-switchers grow as well as their non-switched nestmates. For a test, I performed an experiment in the Barn Owl Tyto alba a non-colonial species with naturally occurring nest-switching. Single fledglings were cross-fostered between pairs of nests, so that without altering brood size each family was given the possibility to adopt a foreign fledgling. I also visited unmanipulated control broods at fledgling time. Three days later I captured the birds present in experimental and control nests. Cross-fostered fledglings were still present in foster nests as often as their non-switched nestmates and control fledglings, and they showed the same body mass change as fledglings of origin. Thus, foster families tolerated or were unable to expel foreign fledglings from the nest. This study suggests that in the Barn Owl nest-switching is an available option for fledglings to improve survival prospect when their parents are poor food provisioners or when they have difficulty in finding food after independence.