If there is NO swelling, no black scab, no sores - probably not bumblefoot. Plus, I've never seen one of mine, with bumblefoot, acting lethargic.
I'm guessing the lethargy and limping is due to something else - quite possibly an illness. I would keep an eye on them and isolate them - maybe in a kennel or something so that they don't walk around too much and so that you can monitor their behavior and how much they eat, drink, poop.
If you've only had them two weeks, do continue to keep them separate. I also would not give them any antibiotics or other medications which could mask symptoms.
I'm guessing the lethargy and limping is due to something else - quite possibly an illness. I would keep an eye on them and isolate them - maybe in a kennel or something so that they don't walk around too much and so that you can monitor their behavior and how much they eat, drink, poop.
If you've only had them two weeks, do continue to keep them separate. I also would not give them any antibiotics or other medications which could mask symptoms.