To me, it's looks like a Roundworm, hopefully 
@Eggcessive or 
@dawg53 can take a look at the photo to give their thoughts.
Panacur horse paste (10%) or Safeguard Liquid goat dewormer (10%) can be used.  Both are Fenbendazole, just a different brand and form (paste vs. liquid).   Dosing is the same for both too.
You are correct that the dose is 0.25ml per pound of weight given orally.
Give once, then repeat in 10 days to treat Roundworms Only.
Give 5 days in a row to treat most all worms that poultry can have except for Tapeworms.
Neither formula mixes well with water, so you are better off giving either the paste or the goat suspension orally by weight.
For me, I usually give for 5 days in a row, but if you feel that is too tedious, I would at least treat Goldie for Roundworms (once, then in 10days) to see if that makes a difference.  Worms certainly can affect the overall health and cause some crop issues if there's an infestation.
Oh, just reading and trying to cover everything.  Yes, if all the pullets are similar in weight, get a good guestimate and dose them.  Fenbendazole is pretty safe.
Being hot can be very miserable for them all.  Hopefully you'll get a break in the weather soon. 
Oh, with you feeling a ball now in her crop lower down.  Normally you wouldn't massage a crop that is Sour and fluid filled, but if it's now feeling like a ball with not much fluid, give her a massage when you give the coconut oil and Miconazole, see if you can break it down a bit.  She had a lot of fibrous material in the poop, so she may have a ball of grass(?) or something in there, hopefully this can also be resolved.
If I forgot something, forgive me.  Ask away!