I got this costume for my 7 month old daughter's first Halloween. I was nervous because she was a large baby and was usually a bigger size in clothes than average. I got the size 6-12 months and it fit her PERFECTLY!! The bodysuit was not tight at all and instead there was a little wiggle room left which was surprising because usually if I would have gotten her a 6-12 months in clothes that would be too small. (She was a 12 month in clothes size or higher depending on the style.) The outfit kept her very warm and the head piece stood in place very nicely and didn't move down at all to cover her eyes up and annoy her. So she was very comfy in the costume. The feathers detach by a little button snap and we did detach them once she got too heavy to carry and we placed her in a stroller for the remainder of the trick-or-treating. So I loved that option. Also diaper changes were very easy because of the buttons down the leg. OVerall this was a great costume and we got so many compliments and laughs because it was so cute and funny to see her in it. If you have any questions please feel free to contact me because I know sometimes it's hard buying something online and you have so many questions beforehand.