Not much you can do about it.
You were not legal to have birds in the first place, so the law won't back you up.
It's a waste of time to even complain.
Remember, the police are there to enforce the law only.
Not to make it, or alter it, or make exceptions to it.
They made a mistake telling you "not to worry about it".
What you should do is work to introduce an ordinance allowing hens in your city.
This is happening everywhere nowdays.
Get together with other poultry enthusiasts and make it happen.
Have the law working for you instead of against you.
That's the right way to handle this.
Think of this loss as a positive and make it work for you!
Good luck,
spot