Hi, so I am new to backyard chickens and I just got two chickens last week. A couple of days after getting them, we noticed that one of the chickens didn't move around as much and just stayed in the group while the other two went up in the coop. Whenever she tried to walk, she would flap her wings and drag herself. When we picked her up to see what was going on, we noticed that one of her feet was significantly swollen. We thought she had bumblefoot so we put her in an Epsom salt bath but as I examined her feathers I notice that her left thigh ( same side as swollen foot) is hot, and yellow, had fewer feathers and had three different gross-looking scabs. She also had no scabs on her feet so she did not have bumblefoot. The next day we order antibiotics, Vetercyerin, and we put Neosporin on her thigh that we thought was infected. We planned to take out the scab and hopefully expel the puss from there. The thing is, after the Epsom salt bath her scabs fell off. She is still eating and drinking but can hardly walk and the other chickens step on top of her. Right now, she is sleeping in a dog carrier in the house because I noticed that she was cold outside as she would shiver. After all, she couldn't go up the stairs into the coop. She's also obviously in a lot of pain since she closes her eyes a lot and cries. I also wanted to mention we got her from a pretty not clean place, I didn't know that at the time, I thought all chicken places were supposed to smell really really bad.
Thank you so much if you've read this, I am very worried about my chicken. What should I do?
Thank you so much if you've read this, I am very worried about my chicken. What should I do?

OK, my contrary opinion to what others have offered. I don't ever bring any of my sick chickens to a vet. For the cost of one vet visit, I could replace my entire backyard flock 2X-3X over. I am the vet for my chickens. I am willing to lose a chicken or two, rather than spending all that money on a vet visit. Sometimes I can nurse a sick chicken back to health, sometimes I lose the chicken and it dies, and sometimes I decided to cull the sick chicken so to end its suffering. For me, it's all part of raising small animals and my responsibility to them. My chickens are not my pets, but I do take care of them that very best I can. You should not have to feel guilty about not bringing your sick chicken to a vet. I certainly don't. My limited money is better spent caring for the entire flock, not just one or two sick chickens.