FARM ES cannot provide estimates or industry averages for propane use because it varies tremendously. We would recommend referencing a FARM ES evaluation on a farm of somewhat similar size and style. Use that farm’s propane use as a proxy estimate.
Another option is to find out if the farm has a sense of propane use from a previous year that can be used as an estimate. Or, if the farm knows how much money they spent on propane you could use that to back-estimate the actual usage.
You could also reach out to local extension services for an idea of an estimate.