Hi
Thanks for the clarification - I could do the sums …. in fact….here we go! The quoted mass of “sodium“ is 300mg in 50g, so that would be 0.6g in 100g Or 0.6% by mass. But ”salt” is sodium chloride! Sodium having a relative atomic mass of 23 and chlorine 35.5. Assuming 0.6g of ”sodium“ is not salt, but just the element sodium present, that would be 0.0261 moles which would give an equivalent mass of sodium chloride of 1.53g per 100g or 1.53% by mass of sodium chloride!
Chemistry calculations I can do - how that affects US garden birds I leave to someone who has more experience. However personally I would not use peanuts at all! Fat balls and seed mix for me