What is a good indication of completed growth in eyasses?

The correct indication of completed growth in eyasses, which are the young birds of prey, is when they are hard penned. This term refers to the development of the feathers and the strength of the bird, which shows that it has reached a stage where its skeletal and muscle development support sufficient flight capabilities.

When eyasses are hard penned, it signifies that they have developed fully enough to begin the process of independence, as their feathers are strong and formed in a way that allows them to fly effectively. This is crucial for their survival in the wild.

While full summed might seem relevant, it doesn’t directly correlate to growth completion as hard penned does, which specifically indicates that the bird's physical development is robust enough for future challenges like hunting and flying. Thus, hard penned is the more relevant and accurate choice regarding the growth status of eyasses.