Hi chickenkeeper - Though this seems like good news, I'd be very wary of approaching the problem in this way.  It seems like you are creating more problems for yourself than is necessary to be honest.  Is it that important to you that you lose any sort of good relationship between yourself and your landlords for the sake of keeping a few chickens?

That law does seem reasonably vague on what might constitute "a nuisance" so I'd be concerned that creating a rift between yourself and your landlords might make them try and find small reasons to evict you in order to get someone else who will stick to their rules.

I think a phone call or meeting with them where you explain what you would like to do and how it will be kept clean etc would be the best course of action rather than waving some legal clause in their faces.