We had a Boston Terrier growing up. Why she wasn't spayed, I don't know because we never intended to breed her. She was an indoor dog for all intents and purposes, so it wasn't a huge deal except for when the neighbor's sneaky Springer Spaniel came over and bred her. She had 4 pups and had to have a C-section/spay surgery when she delivered. The pups were bigger than she was laying there in her bed when she nursed them.