Means ± SEM of response variables of the behavioral tests, feather pecking observations and feather damage scoring of rearing flocks housed in an open, closed or party-open system.

Bold number with superscripts a,b,c indicate P-value of <0.05; bold numbers with superscripts x,y,z indicate P-value <0.1>0.05 (different superscript letters indicate pair-wise differences), ” –“ indicate non determined effect due to effects of an artifact of the system on the response variable.