It sounds like a safe solution for the Silkies to be re-homed or else separated from your layer flock. Either way you only need one Silkie roo if you were to keep the Silkies. 3 roos on top of only 1 Silkie hen is not good for the hen - not to mention you don't want brothers breeding to sisters in the same hatch to avoid health issues.
As for cockerels - hens and pullets will gang up on a single cockerel which is why most breeders keep their cockerels separated from females until the cockerels reach adulthood. My friend had 2 five-month EE cockerels that were getting pecked and chased by the hens until she had to separate them. Once the cockerels are grown to adulthood they gain more confidence.
Your NHR roo was developed from the RIR breed and those males will be on the assertive side whether they were chased by hens during their youth or not
