I'd go over and say (in a very polite / friendly tone), "Someone has been reporting my chickens as noisy and smelly. Do you know anything about it? Do you have any problems with my chickens or suggestions?"
Be quiet and observe closely how they respond.
Best case is they engage you in a friendly honest conversation and you find something that works for both of you.
Worst case they either tell you it wasn't them (any chance your animal control friend could be wrong) or they get defensive.
Either way, I'd get it out in the open that:
1) You're aware someone is complaining
2) The police find nothing wrong with it and you're in your rights
If they put up a stink you should definitely tell them that you put up with their dogs.
If they lie, and your 100% sure it is them reporting you, call animal control on their dogs and keep giving them eggs.