The best thing would be a trip to a good duck vet. If the leg is warm she needs antibiotics.
Vetericyn spray probably won't be sufficient at this point.
Until you can get to a vet and/or start oral antibiotics, please start external treatment. She may not need cutting - are there photo's?
Here is something I wrote up about the clear iodine method
Response for Bumblefoot including link to clear iodine method
I would use the foot soak and clear iodine method - worth a try - see how it goes for about ten days, then review and adjust treatment if needed.
If his legs seem rather warm, I would also start him on Duramycin oral antibiotic to protect from systemic infection.
Here is the link to the description of the clear iodine method. Because so many people get a little confused, please bear with me as I point out a few things... The iodine is clear iodine. Not brown. The iodine is placed on the bumble, just maybe 3 drops, right after soaking and drying the feet. Blow on the iodine to dry it. Keep the little one in a safe, relatively clean place during treatment. The feet are soaked, then the iodine applied once. Then 5 or 6 days later, the feet are soaked again and checked. If the scab that should have formed starts to come loose fairly easily, it can be pulled off. In an advanced case this may need to be repeated.
Okay, now the link.
https://www.backyardchickens.com/t/560693/need-input-on-bumblefoot-treatment-in-ducks/20
Please look at post 22