[Elrohwen]

Neither breed is very good with kids. Others already described the heeler temperament and why they don't make a good match with kids. I know one well and while he's fine with kids, he's not particularly comfortable around them either and just walks away.

From what I know about rat terriers, they are not into loud or rambunctious behavior, and similarly will just get out of the way when kids are around.

It could work, especially if the dog has already been around kids, but if you are looking for a dog that will love the kids and love to be around them, a heelerxrat terrier is not a good choice.