Excessive hair loss in a smooth coat JR

Jill on top of the world

I have teh two best Jack Russells in the world. They are brother and sister, well same parents, but one liter apart. Jack is a rough coat and Jill is a smooth coat. They are healthy and happy dogs. I am feeding dry Eukanuba (sorry if that is spelled wrong) and they do well on that. But Jill is a shedder....a big time shedder. She does not scratch or itch. Her coat looks good and her skin is not dry, but she sheds everywhere....White hairs are in everything. She has no bald spots, she looks great, she just sheds....alot. Can you tell me if there is a product or supplement that I might be able to use to help with the shedding.