When I was on my way to work, there was this blue gym with like some level 700/800/900 Pokemon in and I was like holy fuck; then, on the way home, the same gym is yellow with just a level 500 fearow! Like wtf, how has he taken them down???!!!
I never put my best Pokemon in the gym if I claim it, I need it to take down all the others!!
And unless you've got back up you'll probably lose the gym pretty sharpish, kinda hard to defend 1v6 unless you're 2 or 3 times stronger than their Pokemon.
He might have like a 1k cp Pokemon but just dumped the fearow in there.