I'm not a breeder, but I wouldn't breed her again, especially with this male. I think she's too small, and it's better to have the male smaller than the female.
This might ease your mind a bit. My yorkie was an only pup, and his birth weight was 3.5 ounces. So, it's not always true that if there's only one pup, it will get too big.
Good luck! |