I bought two teeny weenie chicks from local feed store that didn't know what they were other than bantams. They had come in as assorted Bantam chicks. I believe one is a black breasted red old English game chicken and I'm hoping the other one is a Japanese bantam. It's a little black fluffy thing with white tips to its flight feathers. It is colored in down just like a barred rock but without the light spot on its head. They are nine days old now and not even close to the size of a nine day old standardbred chick even though their wings are fully feathered...about the size of a two day old standard chick. I'm really excited to find out what they are, it's kind of like casting wildflower seeds out into your garden and waiting to discover what you have!
Im not an expert at bantams, bit I have some BB reds. Your chick doesn't look like a BB red to me, but I'm not the best source... Good luck with your birds!