Ugh how boring NOT to candle. I almost lose desire to hatch, just buy chicks, then why bother... pullets... I suspect that if I didn't candle, I may just buy eggs in a supermarket.
Ok, now I know where you are coming from.
I have a couple questions, is your goal just to candle eggs or to hatch healthy chicks?
If it is the later, which I hope it is, otherwise if you just like to candle candle every egg the chickens lay and never hatch any.. you would not have commented on the infertile eggs if hatching was not important.
So question number 2, Do you disinfect your eggs before placing them in the incubator?
#3 Do you wear sterile or at least clean latex gloves before touching the eggs or reaching into it?
Failure to do either of these can halt development or cause defective birds.
#4 Do you hatch in the same machine you incubate in? Do you ever have staggered hatches in it?
Same thing can happen here, you are asking for dead or disabled sickly chicks if you do this...
I am kind of a hatching nerd/addict. I hatch a fair share of birds in a year. Sometimes I might hatch more in a week than most do in a year or two. If you are candling because you need to find space and want to get rid of the bad eggs, I understand. I may not agree, but understand. Each time you open and even breath into let alone reach into or touch and egg you are opening a path for a pathogen to enter your flock/system.
Believe me I know they can come in on their own, so no sense opening the door for them and inviting them in.
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I'm very sorry. They were so beautiful. 
Very nice. Silver Linings exist! .
