
No crossbreeds can be advertised on Champdogs; and any breeder of pedigree dogs who is also a breeder of crossbreeds will have their membership cancelled.
If by 'Jack Russell' you mean the ubiquitous short-legged farm terrier, they're great ratters but are generally noisy and 'sharp-tempered', especially with other dogs. If you mean the pedigree 'Jack Russell Terrier' they tend to be somewhat more amenable! Border terriers usually make excellent pets as well as capable vermin hunters.