How come each time- I find my silkie chicks dead?

I have personally done alot ton of incubating...since December, many many hatches..

Now I have had a hatch of buff silkies and each one grew up

But each time...other then that time. If I have a silkie in with another group. That's the one find dead

I have tried 3 other times to hatch and purchase a silkie chick..if it's the only one in the group the next morning I find it dead.

Is it because it's just weaker, I can't say smaller because I have hatched a group of assorted bantams and once again it's the silkie I find dead.

Any ideas? So this doesn't happen again

Yesterday when I swore I would never get anymore I just had to when I saw the bin at tractor supply..that is really the only reason I decided on more is because I saw that one bin filled with bantams..and saw one silkie in the group..got more of others.

But yep sad to say the silkie didn't make it..this morning she was dead

Xoxoxoxo