OP, sorry to intrude in your thread, but Lady of McCamley, how many eggs can you put under a silkie? Mine aren't very big. Last time I got too many eggs, but 2 of my girls teamed up for the job and they are bigger than my silkies. You wouldn't be able to hatch many at once under a silkie, would you? Do silkies "co-parent" like my girls did?
It depends on the Silkie and her fluff and "spread."
I have had Silkie hens that comfortably covered 6 to 8 eggs, though I tend to only place 5 to 6 large size chicken eggs, which could be 7 to 8 medium, as I use my Silkies for expensive breed, purchased eggs, and I don't want to risk any. I tend to use more hens and place fewer eggs for those.
For my barnyard mixes, I would place up to 7 or 8 under a Silkie that spreads well...but 6 is the general average.
My bantam Cochins I place 4 to 5 as I find they have more fluff than sense and tend to lose eggs on the outer perimeters, which means the eggs cool and don't develop properly. I don't experience that with my Silkies.
I have had co-brooders in my Cochins, and currently my Cochin and Silkie co-brood. I have not personally had 2 Silkies co-brood, as I've not had 2 Silkies at the same time but mix of Cochins and Silkie, but the Silkie girl I have now did co-brood with another Silkie. (Like I said, if you need brooding queens, go to a Silkie breeder who almost always has a spare to sell for pretty reasonable).
I LOVE my Silkies for brooding. They are awesome. (My Cochins are good too, just not quite as regular nor as sensible as my Silkies).
Guard your bantams well. I had a really nice brooding stable that a hawk decimated when I released for some free range time. I keep my bantams and chicks covered 24/7 in a netted/wired pen now.
LofMc