Start with just a few bites of the new protein, and watch to see how she reacts. If all is well add some to her regular meal of chicken, maybe half and half, and again wait and see. I would add the new meat at breakfast, give her just her regular chicken for dinner. If she is still good the next day, and her poos are firm, you can add a whole meal of the new protein.
By going slowly you can avoid any upset tums along the way. Then she has two types of meat you know she can tolerate, so you can alternate or combine them as you wish. Add the third new meat the same way. I would add a new meat every week if all are being tolerated well. If the dog is sick or has a loose poo, go back to meats you know they tolerate well until things stabilise. Then try the new meat again more gradually.
I usually add organs after a month or so as they will cause loose poo, so better for a dog who is already doing well on raw and digesting bone well. You can add the organs to a bony meal to keep things balanced.