I thought it looked like both intestines and yolk sac too, but either way, the fact it is being absorbed is a very good thing. The fact it was able to poop is also great. I wouldn't be concerned about the chick eating yet, since it's been less than 12 hours since you found it. Maybe dip it's beak in water later today, but it doesn't need to drink yet either. Sounds like it's doing exactly what it needs to, which is sleep, rest and recover.
Is the mostly dried-up mass connected to the inside the chick's vent? As far as Vetericyn spray, you can buy it at any feed store including Tractor Supply. It's good to have it in your chicken medicine cabinet for all types of injuries, but triple antibiotic ointment works well too.
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