Tenant wants the keep honey bees

[James Smyth]

I have a single family investment property located in a small city in upstate NY.  The house is situated on a 0.25 acre property in the city limits. The tenants have been in the house a few years, have taken great care of the place, are paying premium rents, and have expressed they plan to be long term tenants living out their retirement in my rental.

The tenants like to keep busy with projects. The tenants maintain the landscaping well, I have allowed the tenants to make changes to the landscaping, and plant a vegetable garden. 

This past week the tenants requested to keep honey bees on the property.  I'm open minded to the idea and there is a sizable backyard where the tenants could locate the hives. The tenants already got written permission from the city code enforcement and I confirmed with my insurance company that beekeeping wasn't prohibited.  While the insurance company doesn't prohibit keeping bees, they do exclude any damages caused by the bees. For this, I already require the tenants keep a renter's policy and maintain me as a additional interest on the policy.

Has anyone had this come up? What are your thoughts? What would terms to include in a lease addendum be?