Help - 7 month old hen suddenly very lethargic, laid shell-less egg

[Shotgun Lizzie]

I hope she's doing o.k.
Yes, panting could be stress or she may be working on expelling another egg.
The Calcium (TUMS) is important to get into her, so if she's not eating the food with it mixed in, then break the tablet in 1/2 and pop the pieces into her beak one at a time and let her swallow.

I've had some hens gobble TUMS up with no issues, but I had one hen that would eye food or anything with great suspicion and then refuse it. She was like nope, nope! Well, she got pieces put into her beak, she took them. She was also a pill shooter, who knew chickens could shoot a pill across the yard!