Before Metz most of the necks available at flyfishing shops were widely available and much came from India. Various breeds with different patterns and colorations. A fairly wide spectrum of colors, and usually available for handling before buying.
Pick up the neck, flip some of the feathers to check for the spring in the stem and barbels and sizes. Feelings.
The feathers were naturally really triangular.
For a while, breeding the poultry and sustaining strongly reproducing desirable feathers as a filter was done by Bucky Metz.
But what I was told is that George Harvey was greatly involved with making arrangements for Metz to start raising poultry for tying flies.
I was told that he made the arrangements of procuring certain eggs with DNA desired. Came from the upper Mid-West?
The early necks were very good for tyers who didn't need many dozens, but wanted a range of feather selection for making a range of flies to take to the stream.
Also, the selections of desirable colors and the range of feather structures available on each neck made them very attractive. It was easy to pick out different sizes dry fly hackle, wet fly hackles, streamer hackles and other constructions within the flyfishing world.
Some of the stems were easy to use for extended bodies.
Some were used to wrap a body to create segmentation.
Some could have the color strip removed and used for a body wrap. Has that natural lighting in its structure.
Antenna. Legs. Tails - soft and hard - etc.
The long straight hackles of modern fly tying necks allow for ONE feather to wrap around the hook shank to the equivalent of at least THREE feathers wrapped during the old hackle era.
Modern feathers are seemingly very consistent and are definitely strongly appreciated and embraced and serve many needs well, but not all needs.
Different needs for fly construction can highly value the old-style necks and colors.
IMO