Llama beans for fertilizer

Hi, this is my first post. I want to use my llama beans for fertilizer for my garden. However last year I used composted horse manure and my whole garden died. After lengthy research found out it was because the horses eat hay that was treated with Grazon, which is a herbicide. So the fertilizer killed any broad leaf plants. ( which was my whole garden)
I am assuming I will need to feed my llama different hay or will get the same result? I purchased orchard grass because of this but it is very expensive. Does anyone have any experience with this?