The purpose of the study (published December 2012) was to investigate the scale of the use of multiple-bird water bath stunners, the possible alternatives and their respective socio-economic and environmental impacts. Additionally, the study had to examine if phasing out the use of water bath stunning as recommended by EFSA is a feasible option and, if so, under which terms.

It is estimated that there are around 5,300 commercial slaughterhouses in the EU, the majority of which are found in France. Where available, data on slaughterhouse capacity suggest significant differences between Member States in terms of individual capacity. This is reflected by the concentration of slaughterhouse sectors within Member States with a highly concentrated sector in some Member States such as Germany, the Netherlands and Italy and a less concentrated sector in other Member States such as Spain, Poland and Hungary. EU slaughterhouses slaughtered around 5.81 billion broiler chickens and had an estimated economic output between €30.6 to €32.5 billion in 2011.

It was estimated that some 16,000 staff handle live birds across the EU at present. Approximately half of these work in Member States where formal training is required by national law. Just under half work in Member States where there are no formal training requirements, though it is probable that on the job training is provided in some of these Member States.
The majority of poultry in the EU is stunned using multiple bird waterbaths. More precisely:

• 81% of broilers are stunned using waterbaths; 9% using CAS
• 83% of end of lay hens are stunned using waterbaths; 7% using CAS
• 61% of parent stock using waterbaths, and 37% using CAS
• 76% of turkeys are stunned using waterbaths, and 24% using CAS.

The most important driver behind the choice of stunning system is installation and running cost, which is cheapest for waterbath systems. Product quality and revenue is also important with certain stunning systems providing quality advantages for specific end markets which often result in higher revenue, for example for breast fillets resulting from CAS stunning. Other drivers of system choice include access to capital and slaughterhouse size with CAS systems requiring higher investment costs and being most cost effective at higher throughputs.
The costs of stunning systems were compared through a cost model using a number of simplifying assumptions where necessary. The following factors were included in the cost model:

• Installation cost depreciated over a 10 year period
• Annual maintenance cost
• Labor for reception and hanging, and other labor used in the stunning process
• Water for stunning and cleaning
• Electricity for stunning; and, gas for stunning;
The main data sources used were:
o Aggregated estimates of equipment manufacturers (45% weighting)
o Results of the slaughterhouse survey (45% weighting)
o Data from literature and other sources (10% weighting)

Waterbath stunning was found to be the cheapest stunning method, and CAS the most expensive. The highest cost difference between waterbath and CAS is around 1.5 cents per bird. Slaughterhouses with low throughputs (3,000-6,000 birds per hour) present the largest costs difference compared to slaughterhouses with high throughput (12,000 birds per hour with a difference of around 1 cent).

The impact on revenue of different stunning systems is highly dependent on the end market. Three potential mechanisms for higher revenue were identified: access to higher value markets; higher revenue for better quality; and, reduction in losses through trimming and the cost of trimming.

There has been very limited investigation into the impact of different stunning methods on quality. Evidence generally suggests that damage to breast and leg meat is higher with waterbath stunning. In contrast, damage to wing tips and skin is generally lower with waterbath stunning.

In the case of the fresh breast fillet market, it was estimated that losses through trimming and downgrading of the breast could be between €0.011 and €0.052 per bird.

The feasibility of phasing out multiple bird waterbath stunners 

It is considered that, under the baseline, there will be a slight reduction in the use of waterbath systems and increase in the use of CAS systems in the short-to-medium term (two to five years). It is estimated that the proportion of broilers stunned using waterbaths will fall from 79% at present to around 65%, while the proportion of broilers stunned with CAS systems will increase from 21% to around 35%. There will be significant differences between Member States, with no changes in stunning system in some Member States, and significant changes in others.

A complete mandatory ban on waterbaths was considered difficult. There would be positive aspects of a ban; from a political perspective, it would bring the industry into line with the 2004 recommendation of EFSA, and in social terms there would be a positive impact on animal welfare.

However, there were considered to be significant potential negative impacts and problems. Mandatory phasing out would have strong economic impacts on operators, and these would be accentuated for smaller slaughterhouses due to the technological issue of the current lack of commercial alternatives to waterbath stunning systems. It may also be difficult to make changes to a regulatory framework, which was only recently modified. Furthermore, there may be some negative social impacts if consolidation in the sector were to accelerate as a result of such a mandatory phasing out.


Leave a Reply