My son had the same issue. He was born with a full head of dark hair so we only noticed it when he was able to sit up by himself in the tub. Then we could really see it when his hair was wet.
This was when he was about 8 months old or so.
He got plenty of tummy time, he didn't spend all his time in the swing, bouncy chair or car seat.
Some babies don't have enough space in the womb and their heads don't grow properly.
My son was born at the time when "back to bed" was starting so this is also an issues with some babies.
My son got his helmet right before his first birthday and wore it for 3 months 23 hours a day. He had no issues with it.
As most children won't. It actually worked out well for us because he was learning to walk and when he would fall he had protection.
The older a child gets the harder it is to "correct" the skull. If I had this done when he was younger we would have had better results. But we are happy with the ones we got.
It breaks your heart to think your baby isn't perfect, I was not happy with the decision to do the helmet, but am very happy that we did do it.
When your granddaughter is laying in her crib try laying her where her feet were or switch her toys to the other side so she is putting pressure on the other side of the head. And like another M. said, tummy time is a must.
You and your family can go to a consultation with the wonderful people at cranial tech. You are under no obligation to get the helmet, and they can give you some exercises to help with the neck.
This is not always covered by insurance and it not cheap, but I thought it was worth it.
We went to the one in Oakbrook and the people there were very nice.
Good Luck to you and your family.
If you have any other questions feel free to email me.
Mary