Podotheca

Skin of the tarsometatarsus of a chicken (HE): overview

The scaly integument covering the feet of birds is called the podotheca. Scales are structurally similar to the horny layer of beaks, claws and spurs. They are characterized by a strongly keratinized epidermis on top and are separated by inward folds of thinner, less keratinized epidermis.

In most birds, the biggest scales (scuta) are located on the anterior side of the tarsometatarsus and dorsal side of the digits; smaller scales (scutella) are located on the lateral and posterior surface of the tarsometatarsus.  Small scales located on the sole of the feet are called reticulate scales. (terminology as described in Nomina Anatomica Avium).

The micrograph above shows on the right two bigger scales (scuta) and on the left one smaller scale (scutellum).