Ah so cute! Your proportions and line quality are good too. If you are practicing structure you should try your best to show every side of the forms you use, like you did on the horse's pelvis. I can see top, bottom and side planes. However, on the rooster for example, I can see where the cylinder of the neck attatches to the body but not the head. If you added a top plane I could see where the sphere of the head attatches to the cylinder of the neck. Make sure you draw through the shapes to show their perspective and where they attatch to the next form. I hope this makes sense, and it is harder than it sounds. I'm still struggling with it.