I prefer using game birds to train but it's not an absolute necessity. My latest dog Boone was trained exclusively using feral pigeons as that was all I could get during Covid times and he locked up nicely on the first pheasant he ran across during last season. The "flying rats" aren't ideal but will work if you can't find other birds, personally I like using quail as they are easy to keep temporarily and are very easy to dizzy. Good luck with your training