Chicken leg problems. What is wrong w/ my birds?

Okay, a month or so ago, I posted pics of a young pullet who had some kind of infection. Even after talking w/ a vet and sending him pics and all the wealth of knowledge on this board, no one knew what the problem was. Best guess is that she either ate a scorpion or other bug that bit her in the mouth or was bitten or stung by something. Anyway, after a week of seperating her and giving her antibiotics in her water as suggested on the antibiotic packaging, no change. I decided that she seemed to be feeling okay so I would put her back in w/ the rest of the flock and see what happened. Well, for a week, no change. Then one day I went in to see her and she was not walking and the only roo was protecting her from the other birds. Her leg was swollen huge. It all happened in a matter of a few hours because she had been fine just 3 hrs previous. So I removed her and started giving her antibiotics via syringe 2-3 times per day. The swelling and signs of infection in her face are now gone and the swelling in her leg is gone but her leg isn't better. She is still limping and doesn't want to walk on that leg. Her wing on that side is drooping and she's not even trying to keep that leg tucked under. She just lets it fall behind her and flops to a sit. I don't know what to do with her. I don't know how the leg got hurt or if it even has anything to do with the infection.

Then this morning I went out to check on the rest of the flock. My roo was walking around under the heat lamp and seemed just fine. All of them were fine at 7 a.m. When I went back at 9:30, the hens were all outside playing but the roo was laying on his side on the bottom of the coop and couldn't get up. His comb shows signs that some of the hens were pecking at him a little. I stood him up where he stood for a few seconds swaying around like he was drunk and then fell. I did that a couple times. As he would fall, he just flopped and then made no effort to get up. I moved him in w/ the pullet. They're in a smallish cage inside to keep them warm. The pullet turned around and hobbled over to him as soon as I put him in. They're cuddled up together so sweetly but the roo hasn't moved since I put him in. Still has his legs out to the side and is just laying there.

What's going on w/ my birds and their legs!? Is there any hope for either of them?

 

Thanks. I went through both sites and I'm still at a total loss. *sigh*

 

I thought about Botulism too, after reading the links posted in the first response. There is a little mildew on the edge of the hay block I've been pulling from but otherwise nothing. I can't remember any food scraps I would have given them that would have been contaminated in any way. Their feed is from the same bags that I've been giving them for the past week (laying pellets and a little cracked corn). There are brown recluse spiders around but I haven't seen any in their coop. Not to say that there couldn't be one somewhere but there certainly isn't tons or anything. I'm sure I would see them if that were the case. It's so horrible, though. He's just laying there excreting on himself and everything b/c he can't get up to do it. I put food right next to him and eats fine but he can't get up for it. Until yesterday, he wasn't losing weight and was eating fine. Now it seems his feet are okay but his legs are paralized (no change since yesterday morning).

The hen tries to get around but just can't seem to get her leg to cooperate. Otherwise she is okay. Still, though, it doesn't seem like she's got a good life when she's falling on her face and her leg is getting stuck behind her, etc.

Oh, forgot. Both of these birds were vaccinated for Mereks so I doubt that is the problem.

On the link posted above, it says that for Botulism, to fill the crop w/ water 2x/day. How do I do that? With a syringe? Is this something that anyone has had a bird recover from? I'm really wondering if I need to cull him but really really don't want to.