Big belly

I asked here before if I could see growth to a pregnant does belly by 2 1/2 months and I was told by someone that most of the time you cannot even tell they are pregnant by looking at the belly even when they are in labor. I have two does bred at the same time back around August 25th. Both of them have the same degree of growth to their bellies as if its mirror images. (left side is twice size of right) I have other does and no one else looks like this. These two does came in together but they were both narrow when I got them. No one else was bred at that time either except these two.

Is there something wrong with them or would it be pregnancy related? The one with the biggest belly is a 5-6 year old Nubian who has kidded at least 4 times with twins and triplets. I am not sur on the other. What other reasons are there for big bellies? Are they overeating hay?