Pest Control in SFH in NY

[Dan L.]

Single-family home rental, 1/2 acre of land, tenants have lived there for a year, now they are claiming there are mice. The lease clearly says Pest Control is their responsibility. I am in upstate New York, a very tenant friendly state. But is there any reason to believe that I cannot say that Pest Control is the tenant's responsibility? Is there any way to verify that it is perfectly legal to make it their responsibility?  Thanks for any assistance