B.F.J. Reuvekamp

Performance of commercial laying hen genotypes on free range and organic farms in Switzerland, France and The Netherlands

1. A total of 257 farmers with free ranging laying hens (organic and conventional) in Switzerland, France and The Netherlands with 273 flocks were interviewed to determine the relationships between the genotype of the hens, management conditions and performance. 2. Almost 20 different genotypes (brands) were present on the farms. In France, all birds were brown feathered hens laying brown eggs. In Switzerland and The Netherlands, there were brown, white (white feathered hens laying white eggs) and silver (white feathered hens laying brown eggs) hens. In Switzerland, mixed flocks were also present. 3. The overall effect of system (organic vs. conventional free range) on egg production and mortality was significant, with higher mortality and lower egg production among organic hens. In pair wise comparisons within country, the difference was highly significant in The Netherlands, and showed a non-significant tendency in the same direction in Switzerland and France. 4. White hens tended to perform better than brown hens. Silver hens appeared to have a higher mortality and lower production per hen housed at 60 weeks of age. 5. There were no significant relationships between production, mortality, feather condition and use of outside run or with flock size. 6. There was more variation in mortality and egg production among farms with a small flock size than among farms with a large flock size.

Dermanyssus gallinae in Dutch poultry farms: Results of a questionnaire on severity, control treatments, cleaning, and biosecurity

In 2005 a questionnaire has been sent to 1,390 Dutch poultry farmers to investigate the severity of the poultry red mite (PRM) as a pest problem in The Netherlands. The response rate amounted to 31%. As the questions were not independent of each other, four clusters of questions were formed, based on two observed, discrete variables: (1) directly visible PRM infestation, and (2) indirect signs of the presence of PRM. Respondents were distributed over the most common housing systems in The Netherlands and reflected the Dutch situation with regards to housing of laying hens quite well. More than 80% of the poultry farmers reported infestations of PRM. Chicken flocks without PRM problems were significantly younger than flocks where (signs of) PRM infestation were observed. Where poultry was housed in battery cages, more farmers reported problems with PRM infestations, they tend to apply the first control treatment earlier, and repeat it more often than farmers with poultry in other housing systems. When PRM or signs of PRM were reported, farmers more often applied a combination of control treatments. The mean costs paid for control treatments and the costs incurred in terms of production losses were estimated to be € 0.43 per hen in an average flock. Given that there are 300 million layer hens in Dutch poultry houses and that ca. 85% of the flocks are PRMinfested, the overall annual cost to the national poultry industry is estimated at € 11 million. Since the answers to the questionnaire revealed a significant underuse of several measures that could prevent PRM infestation, there is room for improvement by more stringent management.