I agree, it does look like an abscess. I was thinking before, but forgot to say, this can result from eating a spider and getting bitten in the throat by the spider as it's being swallowed.
If it is an abscess (and it certainly looks like it, and of course chooks can get them too) then lancing it would most likely be necessary. Without knowing for sure what it is I probably wouldn't myself, after all tumors both benign and malignant are pretty common in chickens, but many would lance it. A vet trip is out of the question for a lot of chooks so home treatment is what they get.
Artificial antibiotics can be hit and miss though because they kill necessary bacteria etc as well as the harmful, and many abscesses are encysted so the infection can't actually go anywhere without lancing. Once antibiotics are stopped, or even if they are ongoing, the pathogenic bacteria tend to rapidly adapt to them and reproduce much faster than the beneficial counterparts do so it can actually make things worse, all while harming the organism as a whole. They can permanently kill off populations of multiple interdependent species of probiotics in the gut and scar the epithelium so they cannot ever return, which causes ongoing health problems in digesting food, immune response and disease and parasite defense.
I used pine tar on a large cyst on a turkey hen's wattle, without lancing, and it killed the infection, took out the swelling, and a few days later the cyst vanished without a scar to show it was ever there. That's been my experience of using pine/Stockholm tar on many things including gangrenous old fox-mauling wounds and golden staph infections. It has amazing ability to soothe pain instantly, draw out foreign bodies, kill infections, and heal without scarring in most cases. So I'd use that myself. Just the pure stuff you can get at a produce store or anywhere they sell horse products, most likely. It's also sold online and it's a real lifesaver. I use it on various species and myself.
Anyway, good luck with whatever you do.
Best wishes.