I recall that thread. https://www.backyardchickens.com/threads/odd-egg-coating.1410306/ @aart and I both had our theories about what could have caused that strange shroud over the egg. At the time, I had a thought this young hen could have a glitch in her shell gland that could get her into trouble at some point.
If my theory was anywhere in the ballpark, she could have been releasing two eggs at a time from her ovary. Eventually, one could get stuck since the shell gland usually only has enough calcium for one egg each day.
The calcium tablet, one a day, will help her contractions to expel any egg material inside. Calcium also helps to regulate the hen's egg cycle. So, hopefully, this will kill two birds (pun not intended) with one calcium tablet. Continue one tablet a day until this hen is laying normally again.
If my theory was anywhere in the ballpark, she could have been releasing two eggs at a time from her ovary. Eventually, one could get stuck since the shell gland usually only has enough calcium for one egg each day.
The calcium tablet, one a day, will help her contractions to expel any egg material inside. Calcium also helps to regulate the hen's egg cycle. So, hopefully, this will kill two birds (pun not intended) with one calcium tablet. Continue one tablet a day until this hen is laying normally again.

I tried pulling down on the wattles and that just doesn't work. It seems to make them even more intent on keeping their mouths shut! I grab the upper beak with forefinger and thumb and apply enough pressure to get her to open without causing discomfort. Once the beak opens, I slide my thumb inside the mouth to keep it open. I should mention I only have large breeds, so my thumb isn't that much of a mouthful considering these ladies can swallow mice.