Many broiler chickens have serious difficulties walking

The doctoral dissertation of veterinarian Eija Kaukonen involved more than 100,000 birds, and became one of the world’s first studies on the welfare of broiler breeders.

Kaukonen, who defended her dissertation on Friday 26 May at the University of Helsinki, studied the impact of various kinds of litter and perches used at broiler farms on the condition of the birds’ legs.

Broiler breeders and roosters are raised on broiler breeder farms. They live for just over a year, on average. The breeders lay eggs, and the hatching broiler chicks are moved to a separate facility. The broilers are ready for slaughter at the age of approximately five weeks.

Damage to the broilers’ footpads suggests to researchers and veterinarians that there may be issues with the welfare and breeding conditions of the birds. In this study, however, the condition of the litter did not explain the damage to the footpads of broiler breeders.

 “In the broiler breeder farms we studied, the litter was in good condition throughout the production period, but damage to the footpads of the breeder birds nevertheless increased with age,” Kaukonen explains.

An average of 64% of the breeder broilers in the study had severe damage by the time of slaughter, with some variation between farms.

 “It is likely that the footpad lesions are painful, so we must quickly conduct additional research to discover their cause. Internationally, footpad health among broiler breeders has been studied very little.”

Peat improved footpad health, perches ignored

Broiler welfare is compromised by the breeding process which has maximised their growth and an environment which lacks stimuli. In addition, poor litter is known to cause skin lesions on the birds’ footpads.

The impact of various litter materials on footpad health has been studied; however, there is little research on peat, which is the most common type of litter on Finnish broiler farms.

The study showed that litter with peat reduced footpad damage, even though its condition, including its moistness, was not found to differ significantly from other litter types.

The footpads of the broilers were in better condition than the breeder birds’. However, one in five broilers had footpad lesions and one in three had hock skin damage.

According to Kaukonen, damage to hock skin is a more accurate indicator of the litter conditions and general leg health than footpad lesions.

Perches have been thought to promote leg health among broilers, and animal welfare subsidies have been available for their installation. However, the broilers in the study largely ignored the perches.

 “Instead, they would all crowd onto the grated platforms that have ramps,” Kaukonen describes.

According to the study, such grated platforms can promote leg health among broilers, as they were found to improve the birds’ ability to walk as well as reduce limping.

Contact details for the doctoral candidate

Eija Kaukonen

tel. +358 40 559 7278




LVM Eija Kaukonen defended her doctoral dissertation entitled

"Housing conditions and broiler and broiler breeder welfare - the effect of litter condition on contact dermatitis in broilers and breeders, and the effect of elevated structures on broiler leg health" on 26 May 2017 at 12.15 at the University of Helsinki’s Faculty of Veterinary Medicine. The opponent was senior research fellow, DVM, PhD Andrew Butterworth from the University of Bristol, and the custos was Professor Anna Valros.

Address: EE building, Walter Auditorium, Agnes Sjöbergin katu 2.