I'm not trying to be a smartbutt but why can't you return the 50 lb. bag of feed? I don't see why there would be a problem unless its been opened.
If you can find Perina Flock Raiser crumbles they can eat that their whole lives. It's what I'm using.
I'm sorry you're having so many problems.
I've learned that you have to do your own research and get what you need because a lot of people who work at feed or hardware stores have no clue about the things they sell. Where are you located? If you go to the Orcheln's website you can search for stores near you and see exactly how many of what they have in stock at that particular store. (Good way to check before you make the trip there). You could also search for TSC near you. Maybe a different location will have more variety and knowledgable people.