Why are the leg bones of frying chickens filled with red marrow and not yellow marrow?

That's an interesting question! You're right, red marrow is found in the bones of young animals, while yellow marrow is found in the bones of older animals. However, the statement that frying chicken legs are filled with red marrow is not entirely accurate.

Here's the breakdown:

* Red marrow is responsible for producing red blood cells, white blood cells, and platelets. It's found in the bones of young animals and is very active.

* Yellow marrow is mostly made of fat and serves as a source of energy for the body. It replaces red marrow in the bones of older animals as they stop growing.

Frying chickens are still relatively young animals. While they're not babies, they're not fully grown either. Therefore, their bones still contain a significant amount of red marrow, but it's likely that the amount of red marrow in their legs is less than in the bones of much younger chickens.

Here's the key point:

The age of the chicken at slaughter determines the amount of red marrow in its bones. A very young chicken, like a broiler, would have mostly red marrow in its legs. However, an older chicken, even if used for frying, would have more yellow marrow in its legs.

So, while it's not entirely accurate to say frying chicken legs are exclusively filled with red marrow, they do still contain a considerable amount of it due to their age.