I would not put in extra food in the tank just for the shrimp. They will find something whether it is fish poo, bacteria, or uneaten food-they will find it. Also bettas are carnivores. You have to expect them to eat shrimp, it's what they do!
Red, Casanova, Habanero, Falkor, Eragon
Thelma, Babycakes, Black Sheep, Mystique, Dew