You know it just might work but I wouldn't. I do not have much experience with Silkies and as far as EE my experience is the Roos are generally good with humans but some are really hard on the ladies. Keep an eye out for hens hiding and raw backs. Good luck! I hope it works out well for you. :)
Also EE roosters could really hurt Silkie roosters. Everything will seem okay and then one day someone will catch another rooster breeding "his" girl and all hell will break loose. You need to ask yourself why did I buy chicken? Usually most would say eggs.. Some dinner. Feeding 6 roosters...
Young cockerels get along okay but once hormones kick in 6 roosters and only 5 hen is not so great. Your hens will be over bred and the coop will be stressful. I would find homes for 5, Or keep a bachelor pad with no hens in sight. The math is one rooster for approx. ten hens. The three EE...