Another update now that we're about ~3 weeks in since the original post.
Our hen seems to oscillate between days where she's doing great and days where she's just so-so. She has lost more of her feathers than the rest of the flock, so part of me thinks (hopes) that it's from molting and not from further complications with salpingitis / egg-laying issues. (pic below taken a week ago at the peak of her feather loss)
Since the lash egg she passed, she has not laid a single egg, including any lash eggs. I also haven't spotted anymore egg material in her droppings. It seems her droppings are mostly normal, although there have been a few odd ones that are more liquid-y.
The "mild ascites" I was concerned about might not have been ascites. She still has a bit of a protrusion in her abdomen, but when pressing on it, it's not particularly squishy. Maybe this is the way her abdomen has always appeared and it's more noticeable with her molting?
On the "great" days, she'll keep up with the rest of the flock when we let them out for a graze. Usually she'll find a little quiet spot in the yard for herself to rest about ~30 minutes in, but resume playing later. This is consistent with a few of our other hens that have been under the weather, possibly from molting. (pic below taken yesterday after some fun outdoors)
The "so-so" days worry me a bit because she'll be pretty lethargic with her tail pointed straight down (close to 90 degrees to the ground). Sometimes she'll just stand there while ever so slightly rocking back and forth.
This past weekend, she had a stance that looked similar to the egg-bound stance. I gave her another epsom salt bath and she did appear much better afterwards, although like I said above, no egg passed.
I haven't fed her anymore antibiotics since her 5-day course of enrofloxacin.
Diet consists primarily of her layer feed (no more scratch). We've also introduced a hard-boiled egg + yogurt mixed in, fed roughly every other day as she's hard at work growing feathers. Her appetite is good even on the so-so days and absolutely voracious when it comes to those egg+yogurt plates. She's also managed to find herself a few treats when we let her range.
For her water, I've added some nutri drench (~0.25-0.5mL / day). Water is changed every other day.
The original goal was to release her back with the rest of the flock, but as its been quite cold and her plumage is sparse, we've decided to keep her in for a bit longer.
Let me know if there's anything I could do differently and if there are any signs to watch for in her current state.
Also, if anyone has any experience with a hen fully recovering from salpingitis, I'd love to hear about it. Almost all of the posts I've come across online suggest an eventual decline.
