Catch her after dark, when she goes to roost. Much easier then. Wrap her in a towel if she's hard to hold on to. You may have to crate her overnight until you can work on her, or take her to the vet, whichever you decide to do. You can also go out in the very early morning before light, before they get up, and get her off the roost then. I have one that that is the ONLY way I can get ahold of her. When treating a bumblefoot on her, bandage changes were always done then, after dark. Much less stressful on everybody.