Canada

hi i have a female chiwowa crossed with a rat terrior,
shes been with my family for 7 years,
shes a mother goose as she takes care of my pets when they are sick, treating them as her babies,
she never hurt any thing or any one, but she will chase unknown cats away, but anything that we touched shes knows its her new Family! lol

anyways, when she was 2 years old a black lad dog bred her! but she had a miscarriage! soon after and the lab was taken away by its owner so it would not happen again,
daisy is perfectly healthy, now we want to breed her with a pure bred chiwowa!
will it work? becouse someone told us if a small dog gets bred with a big do she will never had babies! and she may be to old?