Table 4. Keel bone defects of free-range hens.
The number and percentages of keel bone damage of free-range hens at 65 weeks of age from different rearing treatments (control, novelty, structural) and ranging patterns (indoor, low outdoor, high outdoor). Values of each category of damages are presented as n (%) but the number of calluses on tips of keels are expressed as least squares means standard error of mean (LSM ±SEM). For the number of calluses on tips, raw values are presented with the analyses conducted on transformed data.
| Treatment | Category | N | Damages n (%) | Spine bending n (%) | Spine bending types n (%) | Callus formation n (%) | Number of calluses (LSM ± SEM) | |||
|---|---|---|---|---|---|---|---|---|---|---|
| Low | Moderate | High | ||||||||
| Rearing enrichments | Control | 91 | 71 (78.02) | 57 (62.64) | 46 (50.55) | 7 (7.69) | 4 (4.40) | 40 (43.96) | 0.71 ± 0.11 | |
| Novelty | 106 | 82 (77.36) | 68 (64.15) | 51 (48.11) | 7 (6.60) | 10 (9.43) | 42 (39.62) | 0.70 ± 0.10 | ||
| Structural | 103 | 73 (70.87) | 66 (64.08) | 53 (51.46) | 8 (7.77) | 5 (4.85) | 39 (37.86) | 0.60 ± 0.10 | ||
| Test statistics, df, P | χ2 = 1.69, 2, 0.43 | χ2 = 0.06, 2, 0.97 | χ2 = 2.79, 2, 0.84 | χ2 = 0.78, 2, 0.68 | F(2,295) = 0.40, 0.67 | |||||
| Ranging patterns | Indoor | 92 | 68 (73.91) | 57 (61.96) | 42 (45.65) | 9 (9.78) | 6 (6.52) | 39 (42.39) | 0.72 ± 0.10 | |
| Low outdoor | 107 | 81 (75.70) | 71 (66.36) | 57 (53.27) | 8 (7.48) | 6 (5.61) | 36 (33.64) | 0.56 ± 0.10 | ||
| High outdoor | 101 | 77 (76.24) | 63 (62.38) | 51 (50.50) | 5 (4.95) | 7 (6.93) | 46 (45.54) | 0.73 ± 0.10 | ||
| Test statistics, df, P | χ2 = 0.15, 2, 0.93 | χ2 = 0.52, 2, 0.77 | χ2 = 2.60, 2, 0.86 | χ2 = 3.29, 2, 0.19 | F(2,295) = 1.31, 0.27 | |||||