I've been tying my caddis, over the years, with both......probably more with deer hair.

My most trusted (accessible) tier these days is Bucky McCormick of Blue Ribbon Flies in West Yellowstone. So, I needed some things today and called their shop. Bucky answered the phone. Now Bucky ties around 900 dozen flies a year for their shop.

I asked him what his preference was in tying Caddis patterns. He said he really likes Cow Elk Hair. He was good enough to go over to their great hair bins and select several nice patches which I intend to use in the near future.

Let me know what your preference is.