Did you have them while they were fully grown? Was the noise manageable with the crow colors? Do you personally think I should just start searching for new homes now that I know the roosters? Or do you think it would be okay to wait a bit longer for my own selfish pleasure, removing the one hen and giving them all no crow collars?
Personally - I think your biggest problem is you've got 5 boys and 1 girl. Having not had silkies, I don't know when they start up with the hormones, but you've got a serious issue unless you can keep your hen separate 100% of the time. Multiple hormone flooded roosters with one hen have been known to gang up- one will hold her down and the others will jump on one after the other after the other. Best case they each individually pursue her non stop even if they don't pin her down and take turns. This can be a life or death scenario for her, because she's not going to be able to get away from them regardless of how much room there is. I know it's hard to picture now, but that day is fast-approaching. If you can't separate them, then those roosters need to be out the door ASAP, yesterday.
So, if it was me, I'd get them on their way starting tomorrow. You can always ask the new owners for pictures as they mature! Also decide for yourself whether you're willing to let them go to a meat home. Because both of mine proved to be good citizens, I held out for what I hope were no-kill homes (again, people can lie!!). It could be different in your area- when I put them up for a nominal fee I got no responses. When I put them under "free stuff" in "farm and garden" I had multiple replies in short order- from there ask the "question" if it matters to you about the above.
The other thing you should look for soonest is pullet/hen companions. She's going to end up all alone because you can't keep any of the roosters, which is a bad thing for chickens. Quarantine procedures should be observed and that takes time. There are lots of threads about this so I'll mention it so you can look into it- maybe easier with day-olds from a hatchery in this respect.
If you can keep them separate and your girl 100% safe, how long you keep them is up to you and your neighbor's tolerance for the crowing. We are allowed roosters where I live- we use the collar because of the coop's proximity to the house and also good neighbor relationships. One rooster was 7 months and the other was almost 5 months. Both were crowing and mating when we found new homes. The collar kept the noise to manageable levels - no where near as loud as an egg-song once I got it adjusted. For young birds, you've got to check every week or two to make sure they haven't grown, causing their collar to be too tight.
With Silkies though, you've got smaller necks, smaller airways-- if you're considering going that route, search specifically for no-crow collar reviews from Silkie owners. Ours are all large fowl. Aside from feather loss under the collar and the "fun" of getting it to the right position for the best noise control, it's been trouble free for us. I kept the collars for the next roos that will come out of my current hatch from the broody. There are mixed reviews about the collar- really spend time reading others experiences, and really look specifically for Silkie owner's opinions. It comes down to an informed choice.