I don't know what to say.

I have worked in pharmacies that had roaches in the empty vials used for drugs! ( next door was a large grocery chain).. at that one location a patient actually got a roach in
her meds! Imagine that! O.O ...it was a temp assignment for me. And eventually that store moved to a stand alone location...NO WONDER!

I have worked in stores, that had mice and rats (2 actually that had groceries next door). Our Liquor manager used to bean them with a yard stick...he was very good at it!)

I have worked pharmacies that were part of a chain like K-mart, which had loose escaped animals.

Our own grocery where we shop has loose parakeets above the check out. In summer there are sparrows who fly in thru the doors!

If you are next to a pet shop, there WILL be escapees. I don't see how they can be 100% vigilant and careful.

I don't know how you should handle it.

1) you can set out d-con and kill them
2) you can set out live traps, but then what would you do about them once you caught them?
3) you can buy sonic emitters and hope it will drive them back?

But I think it is a common problem, and perhaps a losing battle?