If you want to learn more about training and controlling your Jack Russell, my ebook is bound to save you hours of training trial and error and relieve a lot of stress from the process: The Jack Russell Lover's Ultimate Guide to Training comes complete with a full chapter on mix breeds.
Jack Russell female doesn't seem to be growing
We have 3 jack Russell's (2 female and 1 male) they are mum dad and puppy, the puppy will be 2 the end of this year but she still looks the same as what she did when she was 6 months old! She eats well and everything about her seems fine (toilet habits etc). Her dad is a short haired and short legged jack but he's quite butch, her mother has long hair and long ish legs! The puppy is kinda a mixture of the 2 and is the same height as her dad but just doesn't seem to be filling out! Should we increase her food intake or is it just us being paranoid?