What does "full summed" mean in relation to birds?

The term "full summed" refers to the end of the moult process, at which point a bird has acquired all of its new feathers. During moult, birds shed their old feathers and grow new ones, which is essential for maintaining their ability to fly and for insulation. When a bird is "full summed," it indicates that this process is complete, and the bird's plumage is fully intact and ready for its seasonal activities.

While the other options touch on important aspects of bird care and behavior, they do not align with the specific meaning of "full summed." For instance, fully trained birds or healthy birds may still be in various states of moult, and migratory birds may have different considerations unrelated to the feathering process. Understanding the terminology related to moult and feather development is crucial in falconry and bird care, as it directly impacts a bird's performance and health.