Some people say they can tell if eggs are fertile or not just by looking at them but I’m not sure I’m buying that. If you are looking to hatch them the general rule is you keep them until they mold over. Only infertile ones mold. Remove them as soone as you see the first signs of mold. After a few months, maybe 4-5, you can take a small LED pen light and put it on top of the egg shining down through it. If it is fertile you will see what looks like spiderwebs forming, those are veins! Only use LEDs to candle, standard bulbs can scorch the egg and never pick the eggs up to candle them like you see in all the videos. You will cause damage to the embryo and kill it.
Now it’s my turn to ask you a question. How are you going to house and feed 51 chameleons?