Activists tout the happier, healthier life of free-range chickens, according to Poultry Health Today. Veterinarians in Great Britain, however, have expressed concern about their long-term sustainability and increased likelihood of a major bird flu outbreak in free-range production, according to a report in the Daily Mail.

Barry Thorp, DVM, Royal School of Veterinary Studies in Edinburgh, argues that these free-range chickens are more likely to suffer broken bones, higher death rates, and more disease and illness.

• Mortality rate for free-range chickens is eight to 10 per cent; for caged hens, two to four per cent.
• Fractured bones are twice as likely in free-range chickens than caged hens.
• Disease transmission between free-range chickens and wild ducks and birds is more likely as 10 per cent of ducks in the UK carry bird flu.

Currently, free-range egg production accounts for 45 per cent of the British egg market – compared with just one per cent in 1980.