Gertrude is going to need a saddle. @Kris5902 did you have a pattern that you used? I'm going to have to make one this weekend.
I just ordered one on line and based them off of it, but I did take some size pictures of the original, but it (a “medium”) was too big for most of my girls. It was even a little big on Mrs Marans. What Breed is Gertrude? You may want to make it a little smaller. And there is a layer of interfacing or thin batting of some sort between the fabric layers. I sewed my copies out of old jeans, so I skipped that because of the heavier fabric.