https://www.maars.org/ this place is well known in the Midwest. I’ve donated a cage here. They have a ton of cockatoos where I donated a cage. I am not sure if they adopt out anymore, or if they went towards being a sanctuary.
https://www.iowaparrotrescue.org/ I am familiar with this place. They do have all of their parrots examined by a vet. Their parrots are all on a diet like Harrison’s pellets, chop, and they definitely don’t do the all seed/nut diet.
The place I volunteered at is no longer accepting parrots. She is getting up there in age, and from my understanding she’s trying to get out of the parrot rescue business. I don’t think she has a website anymore for this purpose but I do have her phone number.