botched bean saving

I grew black velvet bean this year. I wasn't sure I would get any beans, the vine grew ok, the leaves often turned yellow. I was happy to see beans finally developed in late summer, maybe it was fall, I'm not sure, but it was quite late. I left them on the vine to dry out. We were supposed to get a frost (didn't happen) so I removed the pods, placed them on a tray I use to dry veggies and herbs. I also put butterfly pea pods on the same rack I keep the rack in the barn.
I'm home sick today, but the chickens still have to be fed. I went into the barn to grab a basket for the eggs, and noticed all the black velvet bean pods gone. not even one left. They have only been there a few days. The butterfly peas are all still there.  I'm so bummed, but I should know better. I use the tray to dry garlic, and onions, and never had a problem I just didn't think a critter would steal my beans, that was pretty dumb of me.
My hope was to grow the beans grown in my area, hoping they would grow better. Lesson learned I will have to buy black velvet bean seeds and start over.