At most I would allow a small dog (less than 25 pounds, full grown) and charge a pet fee (pet rent) 

Dog crap attracts rats .

If you decide to allow it, I would add an addendum to the lease stating the rules and possibly getting a pet deposit.

Seems like about half the population has pets these days, so by NOT allowing them, you are cutting potential bookings by half - maybe more, since a pet owner is more likely to go STR versus hotel.

If there is dog odor, there probably is dog hair in the ducts.

As a broker, my biggest pet peeves are hard money lenders circumventing to my clients, not being upfront about fees, asking for a commitment fee prior to issuing loan docs, and "matching" my broker fees, even though I underwrote the file, got the client, and did all of the processing work. 

If you are not planning on renewing them I would not accept a pet. 

How can I find buyers to get into bird dogging for.

That’ll help you stay competitive and attract qualified tenants faster.Also, make sure you’re very clear about your rental requirements in your listing — things like minimum income, credit score, move-in date, and pet policy.

If these are "emotional support animals", you're probably dealing with FAKE doctor letters.- These are actually pets the applicants are trying to avoid paying additional pet fees & rent for.