Large abscess near tail. Treatment advice please!

[Stoney Meadow Maple]

My problem child Pekin has a large ping pong/golf ball sized abscess near her tail. I have an assortment of antibiotics, including Baytril which says it is an anti-microbial which I have listed. I am rather nervous about surgery, and given that it is winter, I don’t mind keeping her inside for a little while, but I don’t want her to acclimate to inside temps and then have to readjust. She is almost 6 and has had multiple rounds with bumble foot, an infected preening gland, etc, she also has amazing projectile poop, which has always seemed a bit odd. I have treated these topically and had reasonably good results, but this is something new and different.
I am attaching some pictures of the abscess, and a list of the meds I have on hand. If any of them are appropriate, please also advise on dosage if possible.
Please and thank you!

 

[Wyorp Rock]

Hopefully someone familiar with Ducks can chime in.
@Miss Lydia @Jenbirdee

Could it be a feather cyst?

 

[Jenbirdee]

Have you soaked her in a tub to get it clean as possible and then felt it to see if it’s hard or soft / fluid filled?
I think topically you can spray it with vetrycin and apply antibiotic ointment (no pain relief added) in between tub soaks
Or bucket soaks with Epsom salt added to the lukewarm water
As far as all those antibiotics, might try the cephalexin https://poultrydvm.com/drugs/cephalexin

 

[Jenbirdee]

This is what majestic Waterfowl sanctuary says about an abscess
http://www.majesticwaterfowl.org/mmissue33.htm

And you will notice they recommend Baytril