I once had a rabbit who showed a lot of those symptoms, he was always shy, and did not like being picked up, he seemed socially awkward almost. He was young too, and started having seizures, he had two that I know of before he died, I never got a complete diagnosis from the vet, but I believe he had epilepsy. Of course my case was a rabbit, and yours in a chicken but i hope you find this helpful, and I wish your chicken good health!!We just got two silkies a couple weeks ago and one of the is acting strange. In the brooder she sleeps a lot and stays in a corner and when the other chickens run out to explore she just stays put. When we try to pick her up she flaps aggressively and starts screaming and then she closes her eyes but she is shaking vigorously. She also just doesn’t seem to be all there. Should we be concerned? She is eating and drinking just fine.