She may be suffering from a neurological disorder or even gotten into something toxic if she is quivering.
Interesting that the crop is empty now, she may have expelled everything the first time when you picked her up. Often a crop issue is a symptoms of an underlying condition or illness...
I'm sorry to hear about your Silkie.
Is she pooping?
How old is she?
Since she has liquid coming out of her beak, she has a crop problem. Feel the crop - what is it like, hard, soft, air or liquid filled, sour smelling, doughy, etc.
Try to keep her upright and massage the crop to see if you...