I am always trying to find realistic bat props. I feel it's all in thie shape and silhouette. Here Is one attempt I made cutting off the wings of a dollar store bat and repositioning them. Wrap him up like a burrito so the thumbs stick out by his head. Fake fur to get that hairy look and wire to hang up ( or 3M stickey hook tape). Repeat around 100 times and you have a colony! Add a pile of guano below them to make it complete.