What could cause a warm, red-tinged foot that's NOT bumblefoot?

[buffy-the-eggpile-layer]

My 18 month old BO seems to intermittently have a red-tinged foot. A few days ago I noticed a subtle hobble or limp but it was barely detectable. She was still getting around fine and jumping up and down from roosts. Since then it seems to have faded, but today I noticed one of her feet/legs look a bit bigger and redder than the other. When I felt each, the reddish one was warm to the touch, the other cool. I inspected her for bumblefoot, which I've dealt with before, and there are no signs of an injury, scab, or localized swelling (just overall that leg/foot seems a bit bigger and pinker). She didn't seem to be limping and I've since caught her running and jumping up/down from roosts. I should note she is my heaviest hen, so I'm wondering if she could of sprained herself or simply has some inflammation from weight bearing.

I don't want to isolate her because she is bright, eating, drinking and being social--and she's already had one tough transition in the past (she tends to attract bullying easily). And she is getting around fine. I'm just perplexed as to what is causing her leg/foot warmth and what I might do to help her. Any thoughts/suggestions?

Here's a photo (foot on left):

 

[CluckerFamily]

I have no idea about this.
Would an epson salt bath help her feet?

 

[buffy-the-eggpile-layer]

I have no idea about this.
Would an epson salt bath help her feet?

That's a great idea! I will check in in her tomorrow and see if she is still warm. I'm guessing it's some kinda mild sprain otherwise I don't think she'd be so willing to run around. Maybe just inflamed bones or joints or tendons or something...