Did I just kill a healthy developing embryo?

So I did the first candling on days 7, 8 and 9.  First candling is supposed to be done only once but there were a few eggs where I cannot confirm whether the embryo was alive or not.  With brown shelled eggs, it’s very difficult to see the web of blood vessels surrounding a dark spot.  So I'm counting mainly on movement inside the shell.  And sometimes my eyes (or my mind) are playing games with me.  With 48 eggs, I cannot do it in one sitting.  I had to take a break in between or else my observations become unreliable.

So this egg id #163 (the first 2 digits signify the date egg was laid and the last digit 3 means it’s the 3^rd egg collected on that day) is a bit tricky.  I candled three times (day 7, 8 and 9).  Today is day 9 and I saw a thin ring around the circumference which according to the book, the developing embryo died early in incubation.  But yesterday’s candling, it was a vague cloudy shadow which meant the embryo died after several hours of incubation.  So I’ve concluded that they embryo has quit growing.  And I cracked it open to analyze the embryo.  It looks like a perfect embryo but I do see some blood but it could have been due to me cracking the egg.  I feel bad because maybe it was a completely healthy embryo that I just killed.  What made me decide to cull it is because I didn’t see any movement when I candled the egg.  If I leave the eggs that are not fertilized or those embryos that have quit growing, my incubator and room will get very smelly because eggs rot and it can contaminate the rest if it exploded.  An exploding egg is apparently something you do not want to happen because it means tossing everything you have in the incubator.

I hope I didn't make a mistake killing egg id #163.  There was no movement on day 9 and there was a red ring around the shell when I candled it.  However when I cracked it open, it looks like a perfectly developing embryo.

So far I had to toss 5 out of the 48 eggs.  4 out of the 5 I tossed were not fertile and one died early in incubation or could also be my mistake (egg id #163).  The rest are progressing just fine.  It’s exciting to see life moving inside the egg.  I still have about 12 days to go before they will hatch and one more candling to do on day 14 or 15.  I will be doing another candling on about 2 days just on two eggs (#173 and #205) as I cannot conclude whether they are alive or not at this point.