Foot ulcers in laying hens have long been observed to varying degrees, with the prevalence ranging from a few individual birds (0–2%) to around 70% of the flock.

The severity of the foot lesions can vary greatly from bird to bird and also between the right and left feet. Generally, mild lesions, such as pronounced calluses (hyperkeratosis), can be distinguished from severe lesions, such as deeper, wart-like structures with or without acute inflammation (‘bumble foot’). Severe swelling without any visible external changes to the skin may also occur.

The design of the perch influences the load on the sternum and the footpads. It is advantageous to use flattened rather than round perches to minimise the localised pressure on the feet and sternum. Round perches also make it difficult for hens to walk along the perch. In addition to the shape of the perches, the number of elevated perches is also important. Laying hens like to rest at the highest point of an aviary, so there should be sufficient comfortable perches available there. This prevents unsuitable housing equipment from being misused as a perch.

 The contamination of perches with droppings could also have a significant impact on the health of the birds, although further research is needed in this area. Furthermore, as is the case with broiler chickens, the moisture content of the litter is likely to be a significant factor. In some cases, healing processes can also be observed, which may be linked to a change in contact with skin-irritating substances from droppings on perches and in the litter. The material used is also relevant. Wooden perches, for instance, pose a risk of micro-injuries from splinters and are more difficult to clean. Furthermore, litter materials, such as awns from cereal straw, can cause micro-injuries that become inflamed or lead to wart-like growths. There is a particular risk of secondary infections with this type of footpad injury.

Brown hens show proportionally fewer cases of severe pad inflammation than white hens. However, the causes of these breed-specific differences have not yet been clarified.

In cases where the ball of the foot is visibly severely inflamed and swollen from above, ‘toe pecking’ may occur, as the inflamed tissue bursts open or is sometimes pecked at by the birds themselves. These wounds are highly attractive to other birds for pecking, which in the most severe cases can lead to toe amputation.

In her presentation, Dr Christiane Keppler highlighted the following risk factors for footpad health:

• Housing facilities (perch shape, perch material, cleanliness of perches)
• Condition of the litter (moisture, level of soiling)
• Micro-injuries caused by housing equipment or litter
• Genetic influence (increased incidence of inflammation in white hens)
• Possibly also the triggering and exacerbation of footpad disease by pathogens already present in the house or through vertical transmission
• Free-range rearing has a positive effect on footpad health when the outdoor runs are well maintained

Bedding is likely to be of particular importance for hen health. At its best, the material is dry, loose and has plenty of texture. Ideally, the bedding should be 5 cm deep. It should consist of a variety of materials that are of interest to the hens. The moisture content of the litter is influenced by the house climate, the access to outdoor runs, the consistency of the droppings, the litter material, litter management and the season, as well as the activity of the birds.

To assess the current status of foot health within the flock, an individual assessment of the laying hens is necessary. The M-Tool, for example, can be used for this purpose. https://www.ble-medienservice.de/0049/mtool-eine-managementhilfe-fuer-legehennenaufzucht-und-haltung. This involves assessing toe injuries and the condition of the footpads using a rating scale of 0, 1 and 2.