Yes I am in total agreement that a hen usually knows best....but a hen doesn't know anything about shipped eggs. The air cells in shipped eggs are just way to fragile for a broody who obviously does not know any better and treats all eggs the sameSome observations --
I'm fairly new to chicken breeding, not an expert by any means. Please keep that in mind.
Last week I pulled some eggs from my incubator for my good Silkie broody. Although all six had been in the incubator the same amount of time, two candled vigorous, two a bit behind them in development, and two candled inconclusively. (I stink at candling.)
The second day she kicked out the inconclusives. I was pretty sure they weren't good anyway.
The third day she kicked out the two that were less developed. I candled them several times that day and there was no movement. I think the hen knew they were dead.
My conclusion is that the hen knows what she's doing. Not positive, of course, but it looks that way.
On a different note, I had a first-time broody (not CL) attack three just-hatched chicks, killing two of them.
And I had a good first-time broody (a Silkie) abandon her following year's nest. I'm not sure why.
On another note, both Silkie hens were happy to adopt a bunch of week-old chicks, even though neither was broody at the time. I just plopped the chicks in front of them, watched, and the hens tucked them under their wings and raised them well.
edited for clarity
