Improving animal welfare in livestock farming is a challenge that many sectors of the industry are currently seeking to address by finding solutions and exploring new approaches. This is also the case in the laying hen sector, where feather pecking and cannibalism continue to pose daily challenges for many farms, as beak trimming has been discontinued since 2017 on animal welfare grounds. But what factors trigger these behavioural disorders? And how can they be minimised or eliminated altogether? Over the past three years, the Lower Saxony Chamber of Agriculture, in collaboration with the University of Veterinary Medicine Hannover Foundation, has been working intensively on these questions as part of the model and demonstration project ‘Feeding and enrichment under scrutiny for improved animal welfare in pullet and laying hen farming (Layer HACCP)’.

In collaboration with 19 rearing and laying hen farms in Lower Saxony, Mecklenburg-Western Pomerania, North Rhine-Westphalia and Hesse, weaknesses in husbandry practices that lead to behavioural disorders and health problems were identified. In a second step, measures were developed to offer rearing and laying hen farms practical solutions for addressing these issues in their day-to-day operations. During an online seminar organised by the State Research Institute for Agriculture and Fisheries of Mecklenburg-Western Pomerania, project staff from the Lower Saxony Chamber of Agriculture and the University of Veterinary Medicine Hannover presented their findings and discussed them with the audience.

Stress-free acclimatisation of pullets 

Following the introductory project presentation by Jule Schättler of the Lower Saxony Chamber of Agriculture, Dr Peter Hiller, also a member of staff at the Lower Saxony Chamber of Agriculture, began his presentation by highlighting several critical control points in pullet rearing relating to feeding. One of the most important critical control points is the transfer of pullets to the laying hen house. Dr Hiller considers it essential for laying hen farmers to first obtain information on how the birds were reared at the rearing farm. Questions regarding the previous housing system and the housing environment – in terms of feeding times, lighting, enrichment and climate control – are essential for ensuring the pullets settle into the laying hen operation without stress. Only by taking this preliminary information into account and integrating it into the new housing environment can the transfer be carried out with minimal stress.

According to Dr Hiller, it makes sense to move the pullets into the laying hen house in their 17th week of life. The target daily feed intake at this stage is approximately 70 to 75 g. A gradual transition of the feed from pullet rearing feed to pre-laying feed and finally to complete feed for laying hens is highly advisable. The feed transition must be carried out gently, and the timing of the feed change depends primarily on body weight rather than the age of the birds.  It is not only underweight birds that can pose a problem; even heavy pullets that eat well must be gently brought into laying. In the first few weeks after transfer, it should be noted that weight development is not complete until the 30th to 35th week of life. At the start of laying, pullets still have higher nutritional requirements, taking into account both the needs for egg production and for growth. Weight stagnation or reduction must be prevented at all costs during the transition phase. This is why the calcium requirement necessary for shell formation should be increased gradually over several days using a pre-laying feed. In the event of a radical switch from pullet starter feed to layer starter feed, feed intake may drop significantly under certain circumstances. Daily monitoring of the amount of feed and water consumed throughout the day during the transition phase is absolutely essential. It is also important to select a lighting programme based on weight rather than age.

Successful health management

The second speaker, Dr Birgit Spindler from the University of Veterinary Medicine Hannover Foundation, presented various important animal health aspects of pullet rearing. Spindler emphasised that only a healthy pullet will become a high-performing laying hen. The weekly mortality rate can provide an indication of the health status of the flock. The weekly mortality rate should be below 0.13 per cent. Rates exceeding 0.25 per cent should alert the farmer and prompt them to check the flock’s health for potential weaknesses in order to implement appropriate countermeasures. Further indications of health problems in the laying flock include the flock becoming fragmented or weight gain falling below recommended levels. If these problems arise, the causes should be investigated and a vet consulted if necessary.

Prophylactic biosecurity measures are also of great importance for maintaining stable animal health. According to Dr Spindler, adherence to the following aspects is part of successful health management:

• Restricting staff movement
• Adherence to standard hygiene rules, such as the use of a hygiene airlock and the farm’s own protective clothing
• Keeping a visitor log to document the movement of people
• Storing feed, bedding and other materials that come into contact with the animals in a way that is secure against wild birds
• Regular rodent control
• Thorough cleaning and disinfection after each visit.

Vaccinations are an important element of preventive healthcare

Vaccinations also provide good protection for pullets and laying hens as part of preventive healthcare. These are administered via drinking water or by injection. However, although vaccinations offer many health benefits, they place a particular burden and cause stress for the animals. Therefore, the timing of vaccination should not coincide with the move to a new housing unit, and the time the animals are restrained should be kept as short as possible. The decision on which method of administration to use and how many vaccinations to carry out simultaneously should be made with animal welfare in mind. Providing post-vaccination feed supplemented with vitamins C and B as well as oregano extract can mitigate any potential weight loss at the time of vaccination.

Enrichment materials and use of outdoor access

At the end of the online seminar, Anna Riedel, also a member of staff at the University of Veterinary Medicine Hannover Foundation, presented a few further important aspects regarding enrichment and access to outdoor space. When selecting suitable enrichment materials, it is important to use materials that are safe and hygienically sound. Ideally, these should be provided continuously from the first day of life until the end of the animals’ time in the facility. Pecking stones, for example, are available in increasing degrees of hardness. If feather pecking or other behavioural disorders occur, alfalfa can provide initial relief as a source of roughage. It is important that, where possible, all birds have access to the enrichment materials. If behavioural disorders nevertheless occur, it is advisable to introduce new enrichment materials to provide more variety. When using an outdoor run, legal regulations must always be observed. For instance, a space requirement of at least 4 square metres per hen must be provided, to which the laying hens must have access by 10 am at the latest. In addition, this area must offer shelter, which may consist of trees, shrubs or suitable shelters. 

Author: Patricia Lößner, State Research Institute for Agriculture and Fisheries, Mecklenburg-Western Pomerania