Gestation stalls were removed from pig production systems in the UK a decade ago and by the end of this year European legislation will see them phased out across the EU.

The move in Europe has caused some concern among pig producers, many of whom, despite having had a decade to prepare for the new regulations, are ill-prepared.

Recently Spanish pig farmers expressed their fears over the move and estimated that it would cost them about €250-€300 per animal producing a total investment of more than €700 million to make the changes.

The move by McDonalds in the US has produced some positive responses from the industry and animal welfare groups and activists.

"McDonald's believes gestation stalls are not a sustainable production system for the future," said Dan Gorsky, senior vice president of McDonald's North America Supply Chain Management.

"There are alternatives that we think are better for the welfare of sows.

"McDonald's wants to see the end of sow confinement in gestation stalls in our supply chain. We are beginning an assessment with our US suppliers to determine how to build on the work already underway to reach that goal. In May, after receiving our suppliers' plans, we'll share results from the assessment and our next steps."

Animal welfare expert and renowned scientist Dr Temple Grandin said: "Moving from gestation stalls to better alternatives will improve the welfare of sows and I'm pleased to see McDonald's working with its suppliers toward that end.

"It takes a thorough plan to address the training of animal handlers, proper feeding systems, and the significant financial investment and logistics involved with such a big change. I'm optimistic about this announcement."

The move has also been backed by the Humane Society of the US.

"The HSUS has been a long-time advocate for ending the use of gestation crates, and McDonald's announcement is important and promising," said Wayne Pacelle, The HSUS' president and CEO.

"All animals deserve humane treatment, including farm animals, and it's just wrong to immobilise animals for their whole lives in crates barely larger than their bodies."

The American Humane Association also commended McDonald's proactive position to require their pork supply chain to be gestation crate-free.

"This leadership on the part of McDonald's will not only advance the welfare of millions of animals but will most likely encourage others food service providers and retailers to follow suit," said American Humane Association President & CEO Dr Robin Ganzert.

McDonald's said that already a number of its suppliers including Cargill and Smithfield Foods had been making significant progress in adopting commercially viable alternatives.

However, there has been a more muted response from the US pig producers.

A statement from the National Pork Board said that the move had been for commercial interests and that there are several systems including the use of gestation stall that have welfare friendly aspects.

"The National Pork Board recognises that food companies, including McDonald's, make decisions in the best interests of their businesses," the National Pork Board said.

"At the same time, the National Pork Board maintains the position, supported by the American Veterinary Medicine Association and the American Association of Swine Veterinarians, that there are numerous ways, including sow gestation stalls, to provide proper care for sows.

"Each housing system, including gestation stalls, open pens, free-access stalls and pastures, has welfare advantages and disadvantages that must be considered by an individual farmer.

"Regardless of the type of system used, what really matters is the individual care given to each pig - a mainstay of our industry's Pork Quality Assurance Plus programme.

"The National Pork Board looks forward to sharing the results of peer-reviewed research it has conducted in the areas of animal care and food safety as McDonald's begins implementing its decision."

McDonald's can expect resistance from some parts of the pig production sector and there could be a struggle because of the large investment phasing out of gestation stall will entail.

If other leading end users in the food service and retail sectors follow suit, then welfare conditions and production practices in the US will be forced to change, but at a cost to the industry, because the cost of new systems is unlikely to be allowed to be passed on to the consumer.

The move in the US following the developments and experiences in Europe also beg the question what will happen in other countries around the world.

Welfare issues are already high one the agenda in Australia and New Zealand.

In New Zealand, sow stalls will be banned by the end of 2015 despite the $20 million cost to pig farmers to change their housing and in Australia, In November 2010, Australian Pork Ltd delegates voted overwhelmingly to pursue the voluntary phase-out of gestation stalls by 2017.

However, there is, at present, no similar pressure to change systems in the world's largest pig producing country - China.

As McDonald's also has a significant presence in China and other Asian countries, the question is raised whether there will be a similar insistence on changes to production methods in these countries as well in the future.