Who goes there (cluck)?

I couldn't believe my eyes - we had stopped at a service station on the motorway and I was stretching my legs. I noticed something unusual over in the lorry park. As I got closer I could see a small flock of hens pacing in and out of the trailers.

As I approached to get in a shot, these two hens came over to check me out. I really felt as if they were on guard and didn't like the look of this potential intruder. I took a couple of photos and then backed away quietly so they didn't lose face amongst their peers.