The socalled "spent hens" are processed in special processing plants. Typical for these birds is a matured skeleton (little cartilage), which is very weak because the egg production caused a lack of calcium (Osteoporose), and because they (especially the battery-birds) had little physical excercise. Before and during processing, many bones are broken, so almost all birds have one or more broken bones after processing. Also typical is the pronounced keel bone. The meat of spent hens is generally used for soup production, the combs can be harvested for medical and pharmaceutical purposes, and the nearly-mature eggs for human consumption. After evisceration, eggs in all stages of development, are visible.