Deer hair will work just fine. I personally think it is less brittle than elk hair and I know it is much more common here in Michigan . Standard Mustad dry fly hooks are plenty light enough for such a heavily hackled fly. You have good hackle in an appropriate size. I don't believe your problems are related to the materials your using. How many turns of hackle are you getting on the body of that #14 fly? Are you tying it in concave side forward?