Ditto - it just depends on the dog AND how one trains the dog.
My neighbor's Weimaraner and Black Lab both have terrible manners because all they do is play with their two boys - lol
Until they come in my barn - they learned a few years back "my barn my rules" and they are very well mannered when they come to visit.
The Weimaraner wanted to chase the horses when she was young but my big Sorrel put the slams to that in a hurry - lol lol
I've had Rottweilers, Dobermans, big dogs of unknown origin. My two current dogs are a Dobe/Rott and Leopard Cur/Fox Terrier. Both are very well mannered in the barn.
I agree little dogs like a Chihuahua may not be as well mannered because they seem to be nervous and yippy dogs by nature.
I honestly don't think there isn't any dog than can't be taught barn manners; some may just take more patience than others