Many insurance companies do not like certain breeds.  

Does anyone have experience allowing pit bulls or other "dangerous breeds" in low income housing units?

While I am a dog lover myself, and totally agree you cannot judge a dog by its breed, liability wise this was a no go for me.  

Also, if they have a restricted breed, and that would cause a hardship (if you'd lose your insurance because one of your tenants had a pit bull, for instance) then you can deny that animal. 

And my pet policy specifically states name, age and breed of the one pet I allow and requires current pet records, insurance liability, etc., and forbids any other pet, including "guest" pets or pet sitting of any kind.  

For pets, you'll have to know which breeds are unacceptable by your insurance carrier for coverage, set a limit on weight and require they show proof of current vaccination and registration.

As mentioned above, Allstate will not allow certain breeds.

Also,  I am hopeful that you have already outlined upfront what pet types/breeds you can or cannot allow, etc.  

But, you don't have that working for you, unfortunately, as it sounds like allowing pets is common.Do other rentals allow large breeds?  

That's not to say people cant snap out of it if they wake up, but our society breeds consumers!