Y.D.
My breasts are the same size, but don't produce the same amount at all ! My right one makes very little milk. My son woudn't take that one, only the left and I didn't know why.
My daughter tried bottles at the hospital and didn't want the breast at all. I have to pump and feed it to her in a bottle. She's almost one now, and I've been pumping this whole time.
The right breast still doesn't make as much and I'm pumping them both at the same time. The right breast makes about 1/3 of what the left one makes. So both of my kids are breasfed mainly by the left one.