A good indication of completed growth in eyases is when the bird is:

The completion of growth in eyases, or young birds of prey, is indicated by both being fully summed and hard penned. "Full summed" refers to the bird achieving a fully developed plumage, which indicates that the feathers have reached their final state and that the bird is visually mature. This is important for flight, insulation, and overall health.

On the other hand, "hard penned" means that the bird's feathers have stiffened and taken on their final form, which further signifies readiness for flight and independence. This change typically occurs once the bird has fully grown and developed the necessary muscle and feather structure to function effectively as a raptor.

Therefore, the presence of both characteristics—full summation and hard penning—indicates that the eyas has completed its growth cycle and is prepared to transition into the next stage of development. The correct choice acknowledges the importance of both aspects in assessing growth in these birds.