Well, it should depend on the average wingspan of the species. Like how Rhys, Cassian, and Azriel are Illyrian. Rowan's animal form is a hawk. So compare Rowan's wingspan to that of an average hawk and THEN you'll get the size of "other parts.
Fate ordained them to be together loll: born on longest night + lord of night = meant to be _______________________________Rhys Rhysand Feyre Night Court ACOMAF A Court Of Mist And Fury Feysand Feyrhys High Lord High Lady of the Noght Court