It depends on the dog and the line, so have more than others, but 8 is a huge litter for bostons. Average would be 3-4. Not sure what you mean by normal size, as the weight standard ranges for 10-25 pounds, which is a huge difference. My female, Pebbles is only about 10 pounds, so on the smallest end of the weight range, while my male, Astro is 18-19 pounds. Pebbles parents were both smaller, 10-12 pounds, Astro's parents were 12 & 19, so it will be interesting to see how the pups turn out.