WELF ▶▶▶ARE
Access to the range is manda- tory in organic production, however, not all hens dare to venture out into the open.
(DW) layer hybrids (100 birds per pen in 6 pens) at between 17 and 38 weeks of age. They were housed in accordance with organic regulations with a stocking density of 5.7 hens/ m2
, a range area of 4.05 m2
further away from the pop-holes the more grass cover was found.
per hen and shade (with 4 green-
house shade cloths (2×10m) per range). Birds were checked weekly on the same weekday. At the end of the experimental period the vegetation in each range was checked for type, cover and height. Clinical welfare indicators (comb wounds, body weight, bumble foot, footpad lesions, hyperkeratosis, keel bone fractures and plumage damage) were measured for all 1,200 birds on the day of placement and on the last day of the experiment.
Parameters Egg production and other parameters were also examined at weeks 22, 27, 32 and 37 (15-20 eggs per pen were exam- ined for egg weight, shell thickness and shell weight). The proportion of hens on the range during the 21 weeks was also monitored. Results showed that the DW used the range more in weeks 17-25 and less in weeks 27-32 than the BB. Fewer hens used the range in week 38 when the tempera- ture dropped and windspeed increased. Ranging distance from the house was also observed with DW having the longest ranging distance in weeks 17-24 while BB took over in weeks 26-38. The change in distance was greater for BB (3-48m) compared to DW (14-30m). A larger proportion of DW used the shelters compared to BB but, once again, weather conditions significantly affected use. Results relat- ed to vegetation cover found that more bare ground was found in BB ranges compared to DW at 55m and 85m. The
10 ▶ POULTRY WORLD | No. 4, 2021
Results of Aarhus University welfare study
• Plumage cover: Worsened for both DW and BB. DW had a worse plumage score at both ages
• Keelbone fractures: Fractures were more likely for DW at 38 weeks than 17 with the prevalence of fractures in- creasing with age for both hybrids
• Foot condition: Prevalence of hyperkeratosis increased with age in both hybrids with BB birds more likely to have it at 38 weeks. However, footpad lesions were higher in DW birds and percentage of birds with bum- ble foot was around 2-3% for both
• Comb wounds: DW were substantially more likely to suffer wounds (32% compared to 7%) by week 38
• Body weight: BB weighed more than DW at 17 weeks and continued to increase the gap by week 38
• Mortality: DW had a higher mortality (1.83%) com- pared to 0.33% for BB. Most common cause of death was ‘egg yolk peritonitis’
• Floor eggs: Percentage of floor eggs increased with age for both hybrids but rose more for DW
• Egg and shell weight/thickness: BB eggs tended to be heavier and have thicker shells than DW at all ages with thickness levels decreasing with age
PHOTO: PETER ROEK
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