cute puppies!

the standard for jack russells: white should predominate (i.e., must be more than 51% white) with tan, black, or brown markings. Brindle shows other breed (such as staffie) in the ancestry. The same with the all black and the black and tan ones probably shows other breed in the ancestry such as Patterdale Terrier or Manchester Terrier. But ofcourse, they can be 100% jack russell in character and like I said cute nonetheless.