Hi,

I wouldn't worry about the dents - this one hatched just fine;



As to the shells thickening I would say it will also be fine - but you will be better able to judge in the last few days before hatching is due when they begin to soften and stop sticking to each other.

If you feel then that they are thick enough to be a worry then candle for veins and cut a v-shaped opening in any eggs that haven't pipped with a day or so of the first one.