Great start mate! I had the same questions when I created my crow rig that is now on BM!
So I started digging for references more. Bigger birds like crows and eagles have visible thighs when they elongate their feet to either grab something or land, much like eagles, falcons & owls. I didn’t knew what was a natural spacing for that so I made mine controllable since with every image references I see slight variations in many aspects. Also, its hard to tell the bird anatomy under all those feathers. They don’t look quite as expected without feathers and those images are hard to find. Here is the only one I could find and I had to use a bit of creative freedom because that one looks more like a Raven then a Crow (ravens are smaller and don’t have elongated fur on their beak on top of the nostrils like crows do). Also I wanted my bird to be versatile, the ability to quickly generate a few different crows or even a raven quickly and just animate them with ease with a hell of a lot of automations (that was the hard part, wings folding, feathers controls, etc)!
If you want to save yourself some huge headaches and lots of time, you could just buy mine.
Sure it seems pricey at $99 but it took over 200 hrs to create (it was closer to 300 but still). So its less then 50 cents per hrs I’ve put on it when you think about it. As a freelancer I usually charge $30/h on non tight deadlines and $60/h on crazy tight deadlines. So if you do the math, its worth anywhere between $6K to $12k.