You've already got some great advice and links here. I hate to hear that someone(s) are apparently working against you, because that will absolutely make it less likely for them to pass a new ordinance to help you. I happen to be a City Admin myself (we're called City Managers here) so I know what she is facing. Let me offer you a bit of very simple advice, and some you and others won't love but may make the key difference....be willing to make sacrafices right up front to show that you are very reasonable and that you are, in fact, empathetic to those who might be oppossed to backyard chickens. Many times in these situation a person comes in thinking their point of view is 100% right and others who disagree or just mean spirited or crack pots, and so on. (In many cases they are! but still) So think about the things that others are most likely to bring up, and concede some of those. Its harder for them to say no if it appears that you are being fair and reasonable and considerate of others and willing to make SOME sacrifices in order to get SOME concessions. One very specific example of this (and one I know some on here will hate) is to acknowledge that not everyone loves to hear a rooster crow at 5 am, know that people are going to fight the ordinance because of this fear, and suggest that they allow only hens inside the City Limits. Besides the effect this will have on the committee and the City Admin, it will also cut back a LOT on the number of people who might otherwise e-mail, call, or appear at a meeting to object the passage of a chicken ordinance. Once you say that "in the interest of not wanting to disturb my neighbors, as much as I hate to conceed the ability to have roosters, I'm willing to give that up if you will at least let me have hens, which make far less noise". It gets rid of a lot of opposition, and makes it harder for the committee to say "even though you are willing to meet us 1/2 way, we're still not going to do ANYTHING for you, but do everything to apease your opposition". Politicians love compromise!!! SO give them the ability to do that. Another good one is to set limits on numbers. If you're willing to limit the number of byc's to 5-10 (as an example, though you could start with a higher number and "let" them reduce the number so it looks like you've once again been "defeated" and had to take less than you wanted) it would help. This will also alleviate the (unrealistic) fears that some people might have that if chickens are legalized then their neighbors might open egg-laying operations with scores or chickens making noise and odors.
Anyway, just some thoughts from someone who's often on the other side. (Though I personally have made sure that my city council has almost NO rules whatsoever governing the raising of chickens! haha.)
Kevin