Gross pathology photograph of a duckling with skin, ribs, keel bone, and abdominal skeletal muscles reflected. Notice marked fibrin deposition along the capsular surfaces. The pericardium is diffusely thickened and lined by similar fibrin. This is a subacute lesion commonly found in natural infections with Riemerella anatipestifer. Cranial to top of image and caudal to bottom of image.