By all means, use those vent holes. I forced a piece of plastic drinking straw onto the tip of a small funnel, and fill through that. Straw's cut to extend close to the wire "floor" so as not to splash water onto the eggs. Works like a champ.Will I still need stones or heat sinks added to my incubator even though it has an outer shell? Oh and can I add water through the vent holes instead of opening up the bator every time? I think that is one of the reasons my friend has such a low hatch rate. Although she has been incubating this year she said half of her eggs die before the end of the 2nd week and was amazed that almost all 19 of mine were still going at end of week 2. She had to pull 1 shortly after then on lockdown she recandled and had to pull 5 more. So we ended up with 13 good ones at lock down, only a couple were questionable. but out of those only 7 actually successfully hatched. But I noticed she would open the incubator to add water. She has the previous model to mine, although I got the newer one it was cheaper than the previous model.
I think because of this first experience of incubating with my friend, I am nervous because this is for my families food. We intend on eating most of what is hatched, unless they are bred for laying.