My understanding is turkeys are a much more recent addition to european cuisine than other birds. What poultry would a Roman have typically eaten in the late empire? How would they have prepared it?
Fortunately there is a cook book from the late 4th or early 5th century CE. That book is Apicius. Keep in mind these recipes would have been for the upper class of society. There is a section on fowl which includes chicken, pheasant, goose, duck and doves. It also includes ostrich and peacock along with a few others. If you'd like you can check out the book at the following link from project Gutenberg.
http://www.gutenberg.org/files/29728/29728-h/29728-h.htm#bki_chvii
You are also correct in turkey being a recent addition to European cuisine. The turkey is among one of the New World foods.