Level of stress in relation to emotional reactivity of hens

Figures & data

Table 1. Indicators assessed during recording analysis.

Indicator	Measurement	Units
W1	Time between placing the bird on the floor in the experimental box and the first movement, e.g. head movements, looking around, but no locomotor activity	Measured in seconds (s), 600 points were assigned when the bird did not undertake any activity throughout the test (600 s)
W2	Time between placing the bird on the floor in the experimental box and the beginning of locomotor activity	Measured in seconds (s), 600 points were assigned when the bird did not undertake exploration throughout the test (600s)
W3	Tnterest in the enrichment elements: water container, commercial feed container, enriched feed container, shelter, mirror; bird's interest was manifested by approaching the object and exploration thereof with the beak, looking at the object standing next to it, or entering the object	Point scale 1–0, where 1 denoted approach and interest in the enrichment elements, and 0 – no interest; max 6 points
W4	Number of squares crossed by the bird	Minimum value – 0 if no exploration of the environment was undertaken; the maximum value depended on the number of squares crossed by the hen
W5	Time spent by the bird on exploration and showing interest in the enrichment elements	Measured in seconds (s)
W6	Time spent by the bird on locomotion throughout the test, excluding the time of exploration of the objects	Measured in seconds (s)
W7	Physiological–behavioural activities, i.e. defaecation, shaking, preening, vocalization	Point scale 1–0, where 0 denoted absence of the activity and a maximum score 4 was assigned when all activities were observed

Table 2. Results of behavioural tests.

Indicator	N	Mean	SE	Median	Minimum	Maximum
W1	150	73.6	161.5	9.0	1	600
W2	150	281.6	236.7	169.0	1	600
W3	150	1.9	1.6	2.0	0	6
W4	150	12	20	5.0	0	112
W5	150	161.2	160.9	124.0	0	561
W6	150	217.0	145.6	212.0	0	544
W7	150	1.5	0.8	1.8	0	4
TI1	150	44.9	49.4	34.0	0	322
TI2	150	25.4	46.2	3.5	0	278

The indicators are defined in Table 1.

Table 3. Corticosterone level (ng/mL) in the feathers of the experimental birds in relation to the experimental factors.

Trait Genetic group	Quality of feathers		Genetic group
	lsm	se	lsm	se
Leghorn (Lg)	4.10	0.12	4.29 a,b	0.21
Polbar (Pb)	4.19	0.18	4.50 a	0.19
Green-legged Partridge (Zk)	0.33	0.33	3.97 b	0.17

lsm: last square mean.

a,b – means marked with different letters differ significantly at p ≤ .05.

Table 4. Correlations between the level of corticosterone in the feathers and the indicators evaluated in the tests.

Indicator	Correlation	Significance
W1	0.07	0.52
W2	0.03	0.77
W3	0.13	0.23
W4	0.03	0.81
W5	0.05	0.63
W6	−0.04	0.69
W7	0.05	0.52
TI1	0.21	0.05
TI2	0.05	0.64

The indicators are defined in Table 1.

Table 5. Corticosterone level (ng/ml) in relation to the probability of the occurrence of behavioural reactions.

Trait	Absence of reaction		Presence of reaction
	Lsm	se	lsm	se
Defaecation	4.14	0.12	4.17	0.16
Preening	3.91^a	0.11	4.61^b	0.15
Shaking	4.16	0.12	4.14	0.18
Vocalisation	4.13	0.11	4.21	0.19

lsm: last square mean.

a,b – means marked with different letters differ significantly at p ≤ .05.