Why not keep them all back until you figure it out, it could be something subtle that your not seeing now. My first thought was that all the normal looking babies have the same kind of head spot as the mom. I have seen normal BP's with head spots, I had a normal baby with a head spot from a pastel x spotnose breeding and one without, along with a spotnose and 2 pastels. But I would think that it is more then just a coincidence that they all have the same spot as mom. If you can't keep them all, then I guess just keep the ones you think look the best and keep tabs on whoever you sell them to if you can, in case something weird pops up down the road. Could be something recessive and may take a few years to find out.