small hackles for soft hackles
Starling is probably the most under-rated skin in tying today and offers not only good substitutes for feathers that are hard to find (snipe, golden plover, etc.) but they also are sized appropriately for small hooks.
Russ' suggestion about the hen necks is a good one that should be heeded but I want to also suggest looking at the wings of different birds, especially the Partridge and Golden Pheasant. The covert feathers are located on the shoulder of the wing and are very good for soft hackled flies and are in sizes that are a bit smaller than those found on the neck or saddle of the bird. Ruffed Grouse is another feather that shares similar characteristics and I'm sure there are many others.
Additionally, with the Golden Pheasant, the coloration of the covert feathers lends itself to substitution for things such as Woodcock, Brown Owl and in some instances even Golden Plover. There are a lot of variations from bird to bird and I think a lot of it has to do with their age or maturity but the ones I have used are nice, sized for flies in the 12-18 range and the wings are plentiful enough that they should be easy and inexpensive to procure.
There are primary coverts, marginal coverts and under coverts. All are good, small and soft and work well for soft hackles.
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