Keeping dual-purpose hybrids is one alternative to the killing of male day-old chickens. However, dual-purpose hens seem to have several additional advantages compared to conventional layers, for instance a lower tendency to develop behavioural disorders, such as feather pecking and cannibalism. In the present study, three batches of conventional layer hybrids (Lohmann Brown plus, LB+) and dual-purpose hens (Lohmann Dual, LD) with untrimmed beaks were observed from 20 to 69(56) weeks of age. Both hybrids were reared under the same conditions and moved to the hen house at about 18 weeks. The animals were kept in a total of four compartments (about 900 hens/compartment) of an aviary system with two replications of each hybrid line per batch. All hens were managed according to standard procedures by the same farm staff. Depending on batch, minor plumage loss on the back was detected in the LB+ ocks at the age of 22 to 25 weeks. Plumage condition deteriorated continuously, so that up to 97% of the LB+ hens showed feather loss to varying extents at the end of the laying period. However, only 4-5% of the LD hens showed slight feather loss on the head and the breast/belly region, which started at the age of 34-41 weeks and remained almost constant until the end of production. Compared to feather loss, integument damage, and thus cannibalism, occurred in the LB+ hens with a delay of 12-21 weeks. With a maximum of 6.5-11.5% injured LB+ hens, a peak was reached at 49-66 weeks of age, depending on batch. In contrast, skin injuries were observed only sporadically in single LD hens (<0.5%). In three consecutive batches, feather pecking and cannibalism occurred in the conventional layer hybrids but not in the dual-purpose hens, though both genetic strains were kept under the same housing and management conditions. Therefore, keeping dual-purpose hens should be considered as an alternative approach to avoid injurious pecking in modern laying hen husbandry.