This is a list of veterinarians that will work with chickens. If you have any to add, please post them on this thread or PM me.
ARIZONA

Dr. Daniel Burke
Cornerstone Animal Hospital
1663 E. Ray Rd #105
Gilbert, AZ 85296
(480) 857-9229
Dr. Ross E. Babcock
1215 E Northern Ave
Phoenix AZ 85020
(602) 944-9661
Some one posted a while back about this guy and I called to see if it was true and it is! Not only does he see chickens but he has developed a very simple proceedure that de-crows a rooster. People ship him birds from all over the country apparently and the secratary said that since she has worked there (a few years) she has not heard of a single roo dieing. It is about $450 bucks for everything including overnight stay and meds and surgery. Obviously he knows all about chickens for regular visits. He is also willing to talk to other vets to describe the surgery he does.
Connecticut

Kensington Bird and Animal Hospital
977 Farmington Avenue
Kensington, Connecticut 06037
(860) 828-7736
FLORIDA

Edgewood Animal Clinic
1708 E. Edgewood Drive
Lakeland, FL 33803
They mostly see exotic birds, but won't turn down poultry.
INDIANA

All Wild Things Exotic
6058 N Keystone Ave
Indianapolis, IN 46220
(317) 255-9453
Kansas

Gentle Care Animal Hospital
Lawrence, Kansas
(785) 841-1919

Close for NW Missouri, too!
Kentucky

Bullitt County Veterinary Center (Dr. Schaaf)
3026 Highway 44 East Shepherdsville, KY 40165
543-3001 or 955-7877 (Louisville line)
He and his wife (both vets) have seen a broken leg chick of ours in the past. They are very understanding of treating chickens as they have LOTS themselves.
MARYLAND

Falls Road Animal Hospital
Baltimore City/County border
MT Washington area
MASSACHUSETTS

Amherst Veterinary Clinic
John Rosseel, Jr.
300 N Pleasant St
Amherst, MA 01002-2088
(413) 253-3073
School of Veterinary Medicine: Foster Hospital for Small Animals
200 Westboro Rd
North Grafton, MA 01536-1828
(508) 839-5395
Minnesota

David W. Wetherill, DVM
1014 N. Dale Street St. Paul, MN 55117
(651) 487-3255
MISSOURI

Dr. Leach
MyZoo Animal Hospital
Boone Industrial Dr
Columbia, MO
NEBRASKA

Dr. Smith
Chance Ridge Animal Hospital
Skyline Dr
Elkhorn, NE 68022
(402) 289-4400
NEW YORK

Rye Harrison Veterinary Hospital 170 North St
Rye, NY 10580
914-921-2000
They are VERY expensive so ask before going and let them know what you are willing to pay. Their estimates are often wrong (I got one that was $200 but my bill ended up being $600!)
Texas

Dr. Kevin Kunde
Marion Animal Hospital
128 West Seguin Street Marion, TX 78124
(830)914-4900
(830)433-0205 After Hours Emergency
Dr. Ray Stuckey
Hwy. 82 E
Whitesboro, TX 76273
(903) 564-5926
I've not actually taken a chicken to my vet, but i know he has his own flock, is very knowledgeable about chickens and has answered several questions I've had.
Utah

Dr. Greg Folland
Tracey Aviary
86 North 70 West
Centerville, UT 84014
This man is a genius, seriously. I would give him a kidney if he needed one. He is so expensive you might need to sell a kidney to keep seeing him, but I have found the funds when it was most important to me. I can't recommend him enough.