I also deal with various phobias. If you want to get over this particular phobia - you could start by being around baby chicks - maybe at a feed store, or if someone has them. They are tiny and adorable - something you can get used to, as they grow you grow along with them.
Since your room mate's chicken upsets you so much, I think you need to talk to her. Explain your feelings and situation - she could help a lot by confining her bird to an escape proof run with a top. Over time you may be able to sit in a chair and observe the bird through the fence. Bit by bit, you could get closer when you feel more comfortable.
If that's as far as you go, that is still a big victory. Everyone is not cut out to have chickens, or dogs, or cats, whatever. If your roommate won't make some changes to accommodate you - you need to rethink suitability . If necessary, getting a different room mate.
@Phobia
I was petrified of birds, any birds! Chickens were not my idea at all, my son and his Dad started out with them. The thought of chickens being in my garden filled me with dread and fear. But as time went on they grew on me. My top tip is to take your time and don't rush to do anything. For me it was a case just sitting and watching them at first. Then I moved on to putting some food through their run. Eventually I managed to stroke one through the wire. From then on things became easier. 
