Hey, we're new to raising chicks and have a 4 week old and 5 week old silkie. They're in a fishtank under a red heat lamp with the temp around 80 degrees or slightly less. The five week old is substantially larger than the 4, twice her size or larger, though they have unlimited access to feed/water. Recently the larger chick has developed what appears to be almost a head tick. Her head tilts to the side, then snaps up straights, tilts back to the side and so on in rapid succession. It doesn't occur all the time but I notice it several times daily. She appears to be fine otherwise, though the smaller chick has never done this. My question is - is this a medical issue? Is there something I need to be doing or giving her to stop/prevent this? Is it a neurological disorder, is she going to be okay? Also, is it normal for her to be so much larger than the other chick and so much more developed? They began around the same size, is the small chick having developmental issues? Thanks so much in advance for the info, this is our first try and we're still learning!!