Absolutely refuse to speak to her anymore. Let her put her money where her mouth is and hire an attorney. From the sounds of it, she won't do that because it will cost her more than she'd make selling the bird. If she persists, tell her you're calling the SPCA on her and you've documented his condition. If you have any witnesses, tell her you have some and they will back you in court. End all contact and if you get harassing calls, report her to the police and they will deal with her.
Word of advice here....Do what minimaker suggests, document with photo's the condition of the bird and detailed notes of day of transaction/transfer....for any legal purposes...If push comes to shove, you
have proof.
I went thru a similar incident with an Amazon (vinney) that was in terrible living conditions....I would of up rooted their house and flipped the house upside down if they didn't give me the bird after paying for it....I'm no mr. nice guy when it comes to abuse of birds. I turn into Ndamukong Suh (Line backer from Detroit lions) when I see a bird in bad condition.