Table 1.
Behaviour of laying hens when either equipped with a backpack or not (medians + interquartile ranges). Significant differences and tendencies as shown by Wilcoxon signed rank tests indicated in bold. *** P < 0.001, ** P < 0.01, * P < 0.05, # P < 0.10. – Behaviour not possible in this situation. Medians displayed without a Z-score indicate that the behaviour was possible, but now shown. GFP: Gentle feather peck.
| Day of equipping – Holding pen |
Day of equipping − Home pen |
2–7 days after equipping |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| No pack | Backpack | Z | No pack | Backpack | Z | No pack | Backpack | Z | |
| % of observed time | |||||||||
| Stand | 70 (57–76) | 28 (15–52)*** | 3.5 | 9 (5–14) | 11 (7–37) | −1.3 | 15 (12–18) | 14 (9–23) | 0.4 |
| Walk | 28 (23–35) | 15 (5–23)* | 2.5 | 21 (14–35) | 8 (2–13)** | 2.9 | 8 (5–12) | 8 (4–12) | 1.5 |
| Preen | 0 (0–1) | 22 (1–43)** | −2.9 | 0 (0–27) | 43 (5–77)*** | −3.8 | 9 (5–21) | 13 (3–24) | 0.4 |
| Sit or lie | 0 (0–0) | 0 (0−32)** | −2.7 | 0 (0–0) | 0 (0–0) | −0.4 | 4 (2–8) | 3 (1–6) | 1.1 |
| Sidestep or reverse | 0 (0–0) | 1 (0–9)*** | −3.4 | 0 (0–0) | 0 (0–0)# | −1.8 | 0 (0–0) | 0 (0–0) | −1.0 |
| Forage | 0 (0–0) | 0 (0–0) | . | 8 (0–29) | 0 (0–0)* | 2.2 | 31 (19–42) | 38 (25–44) | −1.3 |
| Dustbathe | 0 (0–0) | 0 (0–0) | . | 0 (0–0) | 0 (0–0) | −1.6 | 0 (0–4) | 0 (0–3) | −0.4 |
| Eat or drink | – | – | . | 6 (1–66) | 0 (0–10)* | 2.1 | 16 (9–22) | 12 (9–22) | 0.4 |
| Gentle feather peck | – | – | . | 0 (0–0) | 0 (0–0) | . | 0 (0–0) | 0 (0–0) | −1.6 |
| Receive GFP1 | – | – | . | 0 (0–0) | 0 (0–0) | . | 0 (0–0) | 0 (0–0) | −0.7 |
| Floor | – | – | . | 100 (100–100) | 100 (100–100) | −1.3 | 99 (96–100) | 99 (95–100) | −0.7 |
| Perch | – | – | . | 0 (0–0) | 0 (0–0) | . | 0 (0–0) | 0 (0–0) | 1.4 |
| Ramp | – | – | . | 0 (0–0) | 0 (0–0) | . | 0 (0–1) | 0 (0–1) | −0.5 |
| Nest box | – | – | . | 0 (0–0) | 0 (0–0) | 1.3 | 0 (0–0) | 0 (0–0) | −1.0 |
| Frequency (#/hen/min) | |||||||||
| Wall peck | 3 (1–4) | 1 (0–2)** | 2.6 | 0 (0–0.1) | 0 (0–0) | 1.3 | 0.01 (0–0.15) | 0.02 (0–0.11) | 0.1 |
| Peck equipment | 0 (0–0) | 3 (0–6)*** | −3.4 | 0 (0–0) | 7 (4–10)*** | −3.8 | 0 (0–0) | 0 (0–0.07)* | −2.5 |
| Jump or fly | 0 (0–0) | 0 (0–0) | . | 0 (0–0) | 0 (0–0) | 0.7 | 0.05 (0.02–0.07) | 0.02 (0–0.05) | 1.6 |
| Body peck | 0 (0–0) | 0 (0–0) | . | 0 (0–0) | 0 (0–0) | −1.0 | 0 (0–0.01) | 0 (0–0.01) | −1.1 |
| Wing flap | 0 (0–0) | 0 (0–0) | −0.4 | 0 (0–0) | 0 (0–0) | . | 0 (0–0) | 0 (0–0) | 0.0 |
| Stretch | 0 (0–0) | 0 (0–0) | . | 0 (0–0) | 0 (0–0) | 1.3 | 0.02 (0–0.02) | 0.01 (0–0.05) | −0.7 |
| Head peck | – | – | . | 0 (0–0) | 0 (0–0) | −1.3 | 0.01 (0–0.10) | 0 (0–0.06) | −1.5 |
| Receive equipment peck | – | – | . | 0 (0–0) | 0 (0−2)* | −2.3 | 0 (0–0) | 0 (0–0) | −1.3 |
| Receive head peck | – | – | . | 0 (0–0) | 0 (0–0) | 0.4 | 0 (0–0.05) | 0 (0–0.08) | −1.2 |
| Receive body peck | – | – | . | 0 (0–0) | 0 (0–0) | −1.3 | 0 (0–0.01) | 0 (0–0.02) | −0.7 |