...the minor dimpling is nothing unusual...some eggs do and some
don't at this point...more commonly in the latter half of incubation...it CAN BE a sign of low humidity...it probably would help to add a few milliliters (ie. half TEAspoonfull of water at each end...the little cups of water don't appreciably raise humidity levels AS IS...take a paper towel and wad it up so a good portion rises out of the water...this will substantially increase evaporative surface area...this will raise the humidity in the egg chamber...I place 2 layers of paper towel lightly draped over the eggs...add drops of water such that the towels remain slightly wet...this every 3 days or so...this helps incrase the humidity nearer the eggs where it counts...
...only a few 1/8" holes at each end of the egg chamber for a little bit of air exchange...you'll get plenty more when you lift the lid off every 3-4 days to add water as needed...
lastly...place a probe from a digital thermometer in the egg
chamber...or at the least outside the egg chamber in the incubator...I use a mercury AND digital in every incubator to check against each other...should be within about 1F...
finally...small bowl/deli dish of water outside the egg chamber with several layers of paper towels "wicking" over the edge...
to increase humidity in the air surrounding the egg chamber...
...55-57 days go by pretty fast...good luck!
Scott J. Michaels DVM
Serpent City