Table 5.

Comparison of social network measures using HWI between pigs with and without tail injuries within pens of littermates.

Item	Pen ID 1	No. of Victimized Pigs 2	Pig Category		DifferenceM1-M2	p-Value
			Non-Victimized Pigs (M1)	Victimized Pigs (M2)
At 6 weeks of age
Strength	Pen 2	3	0.924	0.742	0.189	0.66
	Pen 4	1	1.267	0.840	0.427	0.19
	Pen 6	3	0.539	0.763	−0.224	0.12
Eigenvector Centrality	Pen 2	3	0.333	0.296	0.037	0.79
	Pen 4	1	0.503	0.309	0.194	0.37
	Pen 6	3	0.307	0.397	−0.090	0.22
At 8 weeks of age
Strength	Pen 2	3	1.022	1.141	−0.119	0.33
	Pen 4	1	1.008	0.966	0.042	0.99
	Pen 6	3	0.847	0.931	−0.084	0.34
Eigenvector Centrality	Pen 2	3	0.340	0.362	−0.023	0.73
	Pen 4	1	0.367	0.340	0.027	0.86
	Pen 6	3	0.335	0.375	−0.040	0.29

¹ Among 6 pens of littermates, 3 pens had victimized pigs of tail-biting. No victimized pigs were observed in pens of other litter origins. ² Victimized pigs were defined as pigs that were recorded maximal tail score 2 or greater during the 6 weeks of nursery period between 4 and 10 weeks of age.