Feathers are carved from the back forward, which is the opposite of how most people would begin.
A wing is made of overlapping layers - the long primaries at the outer edge lie under the shorter coverts nearer the body, and each row overlaps the one below it. If a carver starts at the front and works back, every feather has to be cut around what has already been carved, and the layering ends up shallow and confused.
So our artisans establish the deepest layer first, cutting the long primaries and taking the ground well down between them, then work forward row by row, each overlapping row carved above the last. By the time the coverts nearest the body are cut, the wing already has its full depth.
Each wing is also carved as a separate panel and joined to the back frame afterwards, with the joint hidden beneath the outermost row of coverts - because a wing carved directly onto the frame would have short grain across every feather tip on the outer edge, and those tips are the first thing anyone brushes past.