I have recently hatched 3/5 call ducks and 3/5 silkies , the 4 that failed were all fertile and were fully formed but died in the shell , 60% is Ok I know , but this dying at the last minute is really annoying , anyone else having this problem ?
we've had that a fair bit, with different batches... and lost a whole incubator full of runner duck eggs, most of which were fertile and well developed. no reason known, there was some problem with our electricity, but the incy temp was kept stable.
I put it down to a genetic cause...