Allowing silkies to hatch a out brood

I would like to know what people think about using silkies to hatch out and raise a brood of chicks. I have recently fallen in love with these wonderful chickens, and have heard that they are wonderful parents...roos and hens alike. Also, I have heard that many times a few hens will sit a nest at the same time, and the roo will take over if the hen(s) get off the nest. I was hoping someone could tell me if this is true or not...I have 6 white silkies, (still don't know sexes, but they are in a brooder with a pair of (m & f) mille flurs (SPELLING), and a blue roo that looks similar to the mille flurs but blue, and not spotted). (sorry, forgot what breed he is....YOU'll know, tho! LOL!) I don't know how old they need to be before they lay and go broody, but they were all hatched out in late february, and one of the silkies just started to crow last week. Next year is fine with me, as I have a bunch of (large breed) broody hens right now hatching out my new babies, but I would like to know whatever you feel you can tell me.