I really do not know the answer to this. Personally, I keep the grown ones in the barn and let them free range. Unfortunately, I have lost a few to predators. The big male silkies seem to stay out of danger, but the smaller hens are always the ones that get killed.
Silkie bird can not fly too well. They can not see all that great and they are so docile that predators seem to pick them out.
The other problem with them is that they can not get away from a big roo fast enough and end up getting in trouble with a roo that is too big for them. I have not found one dead yet, but I do discourage any bigger roo from chasing them as often as I can. They are innocent and pretty fragile. The male silkies can be mean, just like any other roo and they MUST be dealt with just like any other roo. Do not think that the roos will be OK, they need the rooster treatment just like the big boys.
The silkie roos will mate with other hens about their size. I have had some pretty interesting crosses !!