When we first got our hens one had a limp, at first we thought it was bumble foot but couldn't see any swelling, eventually took her to the vet. One of her toes had been dislocated before we bought her and this has resulted in a permanent limp for her. The vet gave her an anti-inflammatory injection which really made no difference. She always limps, even now 1 year on, but seems happy and healthy enough. Sometimes she won't perch and I let her have the choice as to where she wants to spend the night, either nestbox or perch. We just accept now that she hobbles around but so long as she's getting around, eating, and she still lays an egg nearly every day, she's hatched out two lots of eggs this year so we're all happy. The vet's bill with the injections came to around £20 (I can't remember the exact figures). If you can't see any obvious signs of swelling or damage and she's still eating and drinking then I'd leave her for a few days, if you're still worried and prepared to spend the money take her to see a vet for your own peace of mind, but I suggest phoning first to make sure they see hens, I had to phone about three before one agreed to see her, apparently having hens as a pet is unusual and you may be at the receiving end of some strange looks ::)