What causes Eggs to Swell?

[Dazmite]

Hi Everyone, so far I have 32 eggs this season, 10 have hatched healthy so far, I have 4 eggs that started to swell quite large. 2 of which split and didnt make it. They were about 7 days from hatch time. The other 2 appear to have movement now and again. Last season my first two eggs were overly large and hatched just fine. Is there something I am doing wrong? I am worried about the rest of the eggs now. I am incubating in a homemade incubator made of a 10 gallon tank with 3 inches of water heated by an UTH as well as a internal submersible heater. Temps are 80 degrees. Two bins filled with perlite moistened to 80 percent humidity. A few of the eggs in this bin were found layed a bit late and seem to be a little dryish on top, but candle fine so, I placed them in the bin with hopes of being healthy. I do not have a humidistat to tell exact humidity, as last season with 3 inside none ever were the same. I even tried adjusting them via sealed salt and water method. Any ideas whats causing this issue?
Thanks in Advance.
Paul

 

[acpart]

I can't tell you specifically. I do know, however, that even if all your eggs candle fine, some just don't make it. Sometimes the development stops early in the process and sometimes it can stop pretty late. I've also had geckos hatch and not survive the hatching. In my best breeding years, I had about an 85% hatch rate for leopard geckos. Note that if you get a significant percentage of mild to not-so-mild deformities (missing toes, leg bones, notched eyelids) your temperature fluctuations in the incubator may be too great. Good luck with the rest of your season

Aliza

 

[Dazmite]

Thank you, so far last season as well as this there have been no deformities at all. At least none that I can see.