If she laid last year, she should have been laying in July and August of this year. Her malnutrition probably kept her from doing so. So the weight gain is good. But get her gamebird breeder feed.
Also, you may want to worm her. You can safely use Safeguard (also known as panacure). Also, Wazine helps in the control of large roundworms.
Be sure to check her for "bugs" (lice and mites). If you can hold her, check around her vent for signs of lice and/or mites. Also on the back of her neck and under her wings. If you see tiny little crawling things, get a good mite and lice spray and spray her with it, being careful not to get it in her eyes. Mites and lice can really deplete a bird. A lot of folks on BYC use DE (diatomaceous earth) in pens and coops and wherever their birds take a dust bath. That also helps in the control of external parasites.
If I can be of any further help to you, please feel free to "PM" me (that means private message me - just in case you don't know that. I've been on BYC forever and I'm still learning what a lot of stuff means and how to go about doing it). But I'll be happy to help you any way I can.
Good luck with your girl. Turkeys are absolutely awesome creatures.