It may be congestion. The red color of blood comes from hemoglobin in red blood cells, which changes with the oxygen content of red blood cells.

It may also be a harmful substance. It is recommended not to eat.

Reason: Because the blood inside did not completely flow out, the mud turned into blood, so the cooked chicken feet were black.

Treatment: Chicken feet are best made into vegetables when they are fresh. Generally, it can be kept fresh in the refrigerator for 1-2 days. If raw chicken feet need to be preserved for a long time, they can be washed, coated with a little yellow wine, wrapped with plastic wrap, frozen in the freezer and naturally thawed when eaten.