Blue Eared Pheasant (white eared and brown eared as well) are my favorite heron subsitutes. I tie them in by the tips and double the feather as I wrap it. If one DEP feather is not long enough to tie more than 3 or 4 turns, simple tie in one feather by the tip, wrap it up the body to the shoulder, and then tie in a second feather by the tip and wrap 2 or 3 turns for a shoulder. No one will be the wiser unless s/he is an accomplished tyer who takes a very, very close look at the fly that 2 feathers were used.
Coche feathers (rooster side tail feathers) are a great spey feather. In fact, these were the original spey feathers as can be readily seen from the description of the feather in "Autumns on the Spey". They are also inexpensive. And you must strip one side of the feather. They do need to be burned slightly in bleach to remove some the web though. This is very easy to do and only takes seconds. Keep a bowl of vinegar handy and after about 5 seconds, transfer the feathers from the water and bleach solution (1/2 and 1/2) to the vinegar to stop the burning. Needless to say do this is a well-ventilated area or the fumes will make you goofy.
Schlappen is also a spey feather I use, and it is a feather that Glasso used on his flies that called for yellow hackle. You need to break down the web a bit on schlappen though by crushing the barbules on the side of the feather you are going to use, stip the other side and tie schlappen in by the butt always.
Dyed ringneck rump feathers work if you need dark brown or black. There is just not a lot of them that are long enough on any given bird.
The Whitiing Spey necks have improved greatly this year over last year; however, the feather barbules are still too fine and limp for good spey flies. The direction the Whiting Spey Hackle is headed I predict that in about 2 years they will be an excellent spey hackle. They are just not there yet.