pecked/gasping silkie chick
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The trauma by the severe pecking is likely the cause of death, possibly internal in the neck area. Was it with other chicks the same age that did this? If they peck any others, keep the injured one separate until it's healed.
Even though your chick didn't make it, it died being comforted and cared by someone.
Good, keep them separated until they have grown more. Is there a broody mom that hatched them as the reason they were with all the others?