Effects of edible environmental enrichments during the rearing and laying periods in a littered aviary—Part 1: integument condition in pullets and laying hens

Edible Environmental Enrichments in Littered Housing Systems: Do Their Effects on Integument Condition Differ Between Commercial Laying Hen Strains?

“…The obtained results regarding integument condition traits provide new insight into several aspects. The positive effects of EM on plumage condition over all strains confirm the results of previous studies [ 6 , 26 , 27 , 28 , 29 , 30 , 31 ]. At the same time, the results are contrary to studies that did not observe such advantages of an EM supply [ 16 , 32 , 33 , 34 ].…”

“…At the same time, the results are contrary to studies that did not observe such advantages of an EM supply [ 16 , 32 , 33 , 34 ]. Thus far, as the main reason for the inconsistent results between the studies, the different EM materials and their characteristics have been discussed [ 31 ]. Furthermore, study-associated differences in the housing and/or management conditions may have triggered these differences.…”

“…However, the GEI results regarding EM effects revealed in our study indicate that the strains may also contribute to the differing findings. Possible causes for the overall reduction in plumage damage in the groups with pecking stones and alfalfa blocks could include (1) the promotion of foraging and feed intake behavior, which is considered a central factor in avoiding feather pecking [ 2 , 5 , 59 ]; (2) the fact that the use of pecking stones has an abrasive effect on the beak horn [ 31 ], making the protruding beak tip less effective for pecking feathers [ 60 ]; and (3) that additional nutrients/active substances ingested with EM reduce the risk of behavioral disorders at the animal nutritional level, as is known to be the case for sodium and crude fibre [ 61 , 62 ].…”

“…Additionally, the GEIs between layer strains and housing systems for mortality were demonstrated within different brown egg-layer strains [ 66 ] and between white- and brown egg layers [ 67 ]. With the exception of the study by [ 31 ], the identification of GEIs in the supply of EM in littered housing systems has not yet been reported, because the majority of previous studies investigated only a single strain [ 6 , 16 , 26 , 27 , 28 , 29 , 30 , 32 , 33 , 34 ]. In furnished cages that were enriched with sand or sawdust, behavior and integument-associated interactions were shown by [ 68 ].…”

“…In pullets, the use of strings or pecking stones and alfalfa bales could reduce the occurrence of feather pecking [ 6 , 29 ]. Moreover, less plumage damage was observed due to the additional supply of maize silage, pea/barley silage, and carrots [ 30 ], as well as pecking stones and alfalfa bales [ 31 ]. On the other hand, other authors did not observe the positive effects of these EMs [ 16 , 32 , 33 , 34 ].…”