I'm a beekeeper as well as a slave to the hens, and if the "bees" are coming out of the ground, they are more than likely ground wasps and not true bees. It is a never ending exasperation to explain to people that not all flying insects are "bees."
My husband used to get walloped every time he mowed the grass in certain spots. We thought we found where they were coming from, but there were actually several colonies. We were able to get rid of them by hanging a lure for them. I'm pretty sure we got it from Lowes for less than $10. It uses a bait that smells like rotting meat but I couldn't smell it at all. Our honeybees never went near it, and by the end of the 1st season, we no longer had any problems with the wasps.
If I might inject a word of caution: Someone on my bee forum kept her hens in the same area as her hives. Normally the bees won't bother the hens, but she decided to inspect during what we call "dearth," i.e. little or no nectar sources coming in. During dearth, bees generally react the same way they would if a bear were invading their honey stores. The bees attacked her and the nosy hens by clustering around the eyes and combs to sting. She lost half her flock that way, and vowed to put the girls up the next time she worked the bees.