So, a few things. If you haven't already, stop feeding her bread. This can swell and mold in the crop and cause sour crop and bacterial infections, which would open up a whole other can of worms. She should be getting her normal feed and one scrambled egg per day with nothing added.
If you need to forcibly make her drink, get a syringe or water dropper and drop water into the end of her beak. If she doesn't take it that way, you can also drop it into the corner of her beak, but you have to take care to make sure you don't give her too much too quickly or she may aspirate it. Keep her food and water nearby so that she doesn't need to walk -- right now, she needs to be contained to keep her from putting pressure on her leg. I also recommend bringing her indoors if you haven't already to minimize the risk of flies; this also makes it much easier to observe her. Her bedding also needs to be changed daily to prevent her from sitting in her own waste, and I recommend using wet wipes to clean around her vent if you see any feces stuck there.
The crack you showed seems to actually be auto-amputation. The leg is infected and a little necrotic -- likely the result of unsterilized shears -- but her body already seems to be separating infected portion of the leg from the rest of her body. Disinfect the crack twice daily (I would simply irrigate it with peroxide) and apply antibiotic ointment once per day. I'd keep her on the penicillin as well, just to make sure the infection doesn't spread further up the leg before it's separated.
It'll likely be a week or two before that portion of the leg fully necrotizes and falls off, but it will eventually. She'll be very sore and the stump will still be an open wound, so it'll need Neosporin and wrapping and she'll have to remain indoors on clean bedding until it fully heals.
Keep in mind that chickens can recover from incredibly extreme injuries. You've done great with her care so far, so don't give up now!
If you need to forcibly make her drink, get a syringe or water dropper and drop water into the end of her beak. If she doesn't take it that way, you can also drop it into the corner of her beak, but you have to take care to make sure you don't give her too much too quickly or she may aspirate it. Keep her food and water nearby so that she doesn't need to walk -- right now, she needs to be contained to keep her from putting pressure on her leg. I also recommend bringing her indoors if you haven't already to minimize the risk of flies; this also makes it much easier to observe her. Her bedding also needs to be changed daily to prevent her from sitting in her own waste, and I recommend using wet wipes to clean around her vent if you see any feces stuck there.
The crack you showed seems to actually be auto-amputation. The leg is infected and a little necrotic -- likely the result of unsterilized shears -- but her body already seems to be separating infected portion of the leg from the rest of her body. Disinfect the crack twice daily (I would simply irrigate it with peroxide) and apply antibiotic ointment once per day. I'd keep her on the penicillin as well, just to make sure the infection doesn't spread further up the leg before it's separated.
It'll likely be a week or two before that portion of the leg fully necrotizes and falls off, but it will eventually. She'll be very sore and the stump will still be an open wound, so it'll need Neosporin and wrapping and she'll have to remain indoors on clean bedding until it fully heals.
Keep in mind that chickens can recover from incredibly extreme injuries. You've done great with her care so far, so don't give up now!