Another thing to keep an eye out is making sure the silkies don't hit their heads on anything. Polish chickens also have the openings in their skulls. I had a polish rooster who was protecting the flock against the lawn mower (All hens safely inside the coop, Rooster was in the run). The rooster was flying all over the place and hit his head and instantly fell over. I hoped it was just a concussion, and I tried to nurse him back to health but after a week and a half of no improvement I put him to rest. He wasn't eating/drinking on his own. He would 'move' on his own, but this consisted of flapping his wings once or twice and then falling over. He never was able to stand on his own. It was really sad.