Hello there! In the past week I noticed a strange phenomenon in our Silkie chicks: they make a kind of short jerk/shake of their heads, every couple of minutes. It looks like some neurological disorder. Has anyone encountered this? I found a couple of threads on the forum, but none with satisfactory replies. Is it a disease? A parasite? They are about 5 weeks old and have never been outside. I still feed them chick starter + some treats.