For the little ones I speak of and as treats, I have two sources on Amazon and just saw my last one was out of stock, but here's the other. They last forever if I'd quit eating them too.I like that idea for prevention. They do get some sunflower seeds in a treat square I put out weekly. Do you use the raw, unsalted shelled sunflower seeds? Right now, I have some roasted, salted ones. I see they have them on Amazon.

https://www.amazon.com/Got-Nuts-Sunflower-seeds-pounds/dp/B00CL3ICL8?ref_=ast_sto_dp