Hello there and welcome to BYC!
Most aggression results from cramped conditions, boredom, a bird is sick or even a bad diet. So make sure you are giving them enough room per bird. Adults need 4 square feet per bird in the coop, 10 square feet per bird in the run. 1/2 to 1 square foot per bird in the brooder. Give them things to do....get them outside for free ranging even if that is for 1 hour a day. In the brooder, same thing...get them out for a field trip each day. Put ladders, mirrors, hanging veggies, pecking blocks, etc...in the coop and run. For chicks in the brooder, put a low cut cereal box in the corner and fill it with dried leaves, alfalfa leaves, chick starter and some sand, branches to play on and a roost bar. Give the birds a once over looking for reasons this one that is being picked on or why the aggressors are aggressive. Look for mites, lice, respirator ailments, etc...Worm them if you haven't done so recently. And with Silkies, it is very important to trim the hair out of the eyes. If this bird that is being picked on can't see, she cannot defend herself. Birds that can't see can't drink or eat properly.
And finally, generally it is one bird that starts the fighting. If this is an overly aggressive bird, you may need to permanently separate this bird out.
Stop by our Silkies thread too for more help with your birds...
https://www.backyardchickens.com/t/297632/silkie-thread
Good luck and I hope you can get this issue worked out soon!