01571nas a2200157   4500000000100000000000100001008004100002260007000043100001900113700001200132245008500144300000900229490000800238520115300246022001401399       2009                            d  c01/2009bSchlütersche Verlagsgesellschaft mbH & Co. KGaHannover1 aS Rettenbacher1 aR Palme00aBiological validation of a non-invasive method for stress assessment in chickens  a8-120 v1223 aNon-invasive methods to monitor adrenocortical activity need thorough validation.Besides analytical issues, the ability of the chosen test system to detect smallchanges in hormone concentrations triggered by stress perception must beevaluated. In this study, we biologically validated a previously established enzymeimmunoassay (EIA) for corticosterone metabolites (CM) in chicken droppings.Adult laying hens were subjected to one hour of transport and in another experimentto 10 min of restraint. Droppings were collected subsequently after eachstressor, over 36 h in total. Additionally, we analysed droppings that were collectedafter the birds first arrived at the experimental site and encountered unfamiliarhousing conditions. Transporting the hens caused significantly increasedmean CM concentrations for 3 h (328 nmol/kg droppings; p = 0.02) compared tobaseline values (101 nmol/kg), whereas after 10 min of restraint, elevated levels ofCM were not detected (166 nmol/kg; p = 0.87). When chickens were confrontedwith the new environment, CM concentrations stayed significantly elevated overthe whole 36 h sampling period ( gt; 313 nmol/kg; p  a0005-9366