Table 3. Effects of litter supply (litter disruption and litter limitation) on feather pecking, fearfulness and whole-blood serotonin in laying hens.

Effects of litter supply	Severe feather pecking	Gentle feather pecking	Feather damage	Stationary person test	Novel object test	Social isolation test	Whole-blood 5-HT	Correlations
Disruption			↑ week 5** ↑ week 10#	↑ week 10#	↑ week 10#	↑ week 5 (ISA)*	↑ week 15*	5-HT at 15 weeks & social isolation test at 5 weeks r = 0.67**
Limitation	↑ week 5 (ISA)*	↑ week 5*
Disruption* limitation	↑ week 5* ∼ week 10#	↑ week 5NS
Effects displayed in:	Figure 3	Figure 3	Figure 5	text	text	Figure 6	text	Figure 7

↑increase due to described effect, ∼ effects dependent on interaction, NS: not significant, ** indicates effects P<0.01, * indicates effects P<0.05, # indicates effects P<0.1, (ISA) effects only valid for ISA hybrid, r =  correlation coefficient, week  =  age of hens in weeks