How to change the laws in Umatilla, Oregon?

It never occurred to me that there would be a law stipulating whether or not I could have chickens for laying eggs. I bought 3 Australorps and 3 RIRs and they are about 5 weeks old now. I had plans to finish their coop construction by the first weekend of May, but I just looked up the ordinances for my city in Umatilla, Oregon (about 7K population) and livestock and poultry of any kind are not allowed at all...even people who breed dogs and cats for a living are not allowed to do that! It seems like the law is pretty severe. I just moved here a year ago from a town that is only 6 miles away (about 17K population) and allows chickens as long as they aren't running free off the homeowner's property (I just checked their ordinances for comparison). I don't understand why my small town is so severe with their ordinances, while I could live in the middle of a huge city like Portland or many of its suburbs and own chickens. I feel a little cheated that a law tells me I can't raise my own hens to feed my family healthier and cheaper eggs. How can I go about changing this ordinance in my town? I have very little experience with things like this.

Dang! I have been trying to convince my parents, who live in Umatitty, to get chickens in their backyard, but they told me it was against the law. . .. Well your post confirms it. Hmmm. . . Im suere everyone there would be for it!