Neighbor Issues with chickens.

Writing here to ask for opinions on what to do because I am at a total loss.

I just had new neighbors move in. They are sweet, understanding, and mature when it comes to the issue I am about to mention; but they are sort of hard headed.

I have had chickens for over 7 years; two roosters and 17 hens in total. One rooster is a total wussy, the other one will defend his ladies but I have them for egg colored breeding **only** since one is a Full-bred Americana I got from a specialized breeder online and the other is a Brahma/Dark Maran mix.

Well, my neighbors got chickens too. One rooster and three hens. Their rooster is young. They keep coming over to our yard which is no problem what so ever... you know, until they start eating my feed I pay like 100 dollars every 6 weeks on and going *into* my chicken coops. (I do not know if they have mites or anything)

So, I spoke with them about it. I wasn't angry since my chickens go into their part of the land sometimes but NEVER their yard. We both agreed to keep them up. (Which they ended up doing for one day then tried to train their chickens by leading them away from our yard with treats.) Okay, cool. I kept mine up for two days and they rarely go between the yard.

Gave it three days and they were back eating my chickens feed.

Okay, see now I am getting a little frustrated, lol.

Today I caught their rooster mating with ours. Cool, chicken things, I wouldn't care if I was planning to hatch chicks here soon and actually wanted their roosters genes, but I **do not at all** because I breed for egg color and its really just starting to be a nuisance to me.

I have already told them multiple times in the nicest way possible to KEEP THEIR CHICKENS in their yard, but I don't want to be too mean because what if my chickens go back over there?

I just don't want their chickens totally free loading off of me and scaring them off hasn't worked.

I don't want to seem like mean neighbor, but I am at my wits end when it comes to it.

Edit; I want to add I am also worried about over-mating with one extra rooster mating with mine since I only have 17 hens to already two roosters.