Different standing crops for organic layers

Summary

In typical organic egg production systems nearly all the feed is imported and fed inside the henhouse. Moreover, most of the hens stay inside the house or predominantly use the area just in front of the hen house. In consequence many systems are exposed to an unacceptable accumulation of nutrients in the most utilized areas in the hen yard. It is the hypothesis that this drawback can be affected if the feeds for a higher degree are based on foraging within the hen yard.
The purpose of this study was to estimate the effect of including standing crops in the hen yard on feed intake, production parameters, recirculation of nutrients in the system and the welfare of the poultry.
Two experiments with different standing crops for laying hens were conducted at Research Centre Foulum in 2004. Each experiments was carried out as a 2x2 factorial split plot experiment with two different crops as the main plots, two types of feed as subplots (concentrate for organic layers versus wheat) and three replications. Each plot totals 200 m2 and in all plots oyster shells and grit stone were added to the feed. 20 hens and 1 cock of the breed “Lohmann Silver” were inserted into each plot for about 4 weeks. In the first experiment the crops consisted of clover grass and a mixture of herbs (buckwheat, tansy-leaf phacelia and flax). In the second experiment crops consisted of clover grass and chicory (Grassland Puna).
Preliminary results show that the feed consumption was significantly different of the two types of feed. Hens consumed approximately 90g wheat daily in both experiments whereas they consumed 129g concentrates in exp.1 and 155g concentrates in exp.2. This probably indicate a higher retention time in the gizzard + a higher consumption of green fodder among the hens fed wheat. Hens fed wheat had a significantly higher intake of oyster shells compared to those fed concentrate. No differences in the intake of grit stone were seen. The hens had a significantly lower egg production per hen per day in the first experiment (LS-means 0.90 vs. 0.70) when hens were fed wheat only, however no difference were seen in the second experiment with LS-means at 0,82 egg/hen/day for both types of feed. In both experiments a significantly lower egg weight were seen when hens were fed wheat. The type of crops had no effect on the egg production. Clinical welfare assessments of all hens that were made at insertion and postponement showed an excellent plumage condition, food health and colour of the comb irrespective of treatment.
Results of feed intake will be interpreted in the light of observations of roughage content in the crop.