Once you plead guilty the deal is done. If you plead guilty/no contest to a misdemeanor than it is a misdemeanor you have plead to. The negotiating to have it reduced to an infraction must be done before you plead no contest/not guilty. The negotiating can be done at any the arraignment or at the pre-trial. You should consider hiring an attorney to do the negotiating for you.
If you are looking to lower the misdemeanor to an infraction, you better lawyer up since it is likely to improve your chances. Many attorneys offer a free consultation. My advice is to speak to one long before your court date. May the attorney can get the matter rejected all together.
The response above is not intended as legal advice since it’s impracticable to provide thorough, accurate advice based upon the query without additional details. It is highly recommended that one should seek advice from a criminal defense attorney licensed in your jurisdiction by setting up a confidential meeting. Moreover, this response does not constitute the creation of an attorney-client relationship since this message is not a confidential communication because it was posted on a public website, thereby publicly disclosing the information, which is another reason to setup a confidential meeting with an attorney.
I am glad you were not accused of "fowl" play as messing with chickens will get the animal rightists in an uproar. Normally if a misdo is going to be lowered to an infraction that happens as some part of a negotiated plea at PTC.