Incidence of leg problems is likely to increase
CIWF fears that, in the absence of legislation to prohibit the use of fast-growing
broiler genotypes, the incidence of leg problems is likely to substantially increase.
An article in World Poultry in 2000 stated that liveweight at 42 days is projected to
increase by a further 575g. (24%) to the year 2005 (van der Sluis, 2000). McKay et al
(2000) stated that liveweight at 42 days is projected to reach 3 kg. by the year 2007 (as
opposed to 2.6 kg. at the time of the paper).
Such increased growth rates could well impose further stress on broilers’ legs and
lead to an increase in the proportion of broilers with gait scores of 3 and above.
Indeed, when Hardiman (1996) indicated that breeders predicted an increase in
growth rate of 600g. to 40 days of age over the next ten years, Kestin et al (1999)
predicted that an increase in growth rate of this size would lead to a deterioration in
walking ability of approximately 1.1 units of gait score, assuming that no active
selection to improve walking ability is undertaken.