I just read your whole thread....and to me it's VERY interesting....
I don't think I would feed her real food until her crop is completely empty- but that's my own opinion. Additionally, foamy poop is often a sign of worms--but may also be due to sour crop...so if it continues to be foamy---then I'd worry about worms...if it "fixes" itself- then it was the sour crop.
So here's my story- with an interesting twist that pertains to your comment about dandruff...
I just recently found my chicken almost dead (a relatively recent rescue who had lots of problems when I got her and I thought she's gotten healthy)- with the exact same bulgy crop description you gave. A huge crop that felt mushy and eventually felt more like clay. She also had some other injuries--so I DID give terramyacin....My case was complicated by seizures and she's now fine, but just now really walking.
I alternated giving her terramycin and a strong ACV solution every 2 hours. I used a syringe, but I did NOT just flush it in her beak- I allowed a drop or two at the tip of the beak and she would swallow it.
I also gave her mineral oil- Now I was in crisis stage, so I gave her a lot- probably 2+ TBSP worth in 12 hours. Mineral oil is preferred over olive oil as it does cause diarrhea and therfore causes a sort of "flushing of the whole system". Had I not had mineral oil on hand...I would have started with olive oil.
I massaged her crop after every ACV/Terramycin/mineral oil treatment.
After her first time having her crop get smaller, I gave her yogurt---only 1tsp at a time spread throughout the day.
I noticed that she wasn't pooping right....but she couldn't get up either--so I massaged her belly--between her legs. She eventuallyl pooped out massive amounts of poop (probably 5-6 poops worth). It was a total stench and very dark green---a lot like cow poop...(probably from some hay or grass?-- I only use hay in the nest boxes-cuz they liked the hay filled nest boxes better than shaving filled ones)
Anyway- once that massive poop went through- her crop emptied all the way and she began to poop normally (but only when I helped her stand).(++something to think about...anyone else have a chicken that couldn't stand and still be able to poop??)
I added cooked oatmeal mixed with yogurt to her diet...again--only 1-2 tsp at a time throughout the day. I eventually added a little bit of feed crumbles into the mix- as I didn't want to overwork her crop right away and while thinking about how to proceed it dawned on me--as she was eating, that she hadn't been outside now for quite some time, and her crop had been completely emptied several times---she needed GRIT!!! Once I added grit back into her diet- she seemed to stabilize and her poops were more consistantly good. I continued to slowly get her back to a "normal" diet by lowering the oatmeal content and increasing the feed crumbles. I added vitamin water..when I had quit the terramycin after 9days--as her wounds were looking great and I feared that if it was the thrush type of crop sourness that started this whole thing, that antibiotics could make it worse. I also wanted to add the vitamin water as she obviously hadn't been getting any nutrients for some time now.
SO TO MY MOST INTERESTING PART COMPARED TO YOUR STORY....
When I first brought her in, her head was full of little scabs, and once those healed and she seemed to have the WORST dandruf. I thought it might be due to dehydration- but by this time she was drinking on her own....then I noticed the dandruf on the head was more than just skin peeling--it seemed thicker and almost crumbly (hard to explain)...so I bathed her and cleaned it really good. It returned and I bathed her again...and again it returned in 2days...so I decided it was probably fungal and began to put anti fungal cream on her head, wattles, and wherever I saw skin peeling. It's been three days of the antifungal cream, and no more crumbly peeling on her head. I'll do this daily for at least a week....don't want to quit too early.
This makes me wonder if she had a fungal crop problem (thrush). If that is the case...it's the ACV treatment that changes the PH of her crop that probably did the trick (along with the mineral oil for the initial emptying of her whole digestive tract).
Mind you all- I usually wouldn't do so many treatments at once- but my chicken was knocking at "the coop door in the sky" when I found her-- I had to treat both her wounds and her crop. Her neurolgical problems--I think were due to her falling off one of her favorite roosting spots --as I found her under that spot on the ground--it's 3feet off the ground and I think she injured her back and possibly got a concussion as well...but that's a whole other story--and she's still recovering from that.
The good news is she's now in her own mini coop outside and walking (albeit with a limp). She's getting better every day! I really thought I had lost her, and it was worth every minute of time to treat her (although DH and all his co-workers seem think I lost a few marbles!---I think I'll withhold fresh eggs from them for a while as pentence for such negative thoughts about chickens indoors during a critical time!)
Anyway- Keep up the good work!
Sandra