well I fed it a small rat which is the same size as a large adult mouse, and i'm also feeding small rats to my 4.5 month old baby ball python with no problem. This boa is about 8 months old @ about 3ft and this meal I think is fine for her since she is growing fast and is twice the of my BP. My 1 yr BP is also on small rats.
So the small rat is a bit large for the 4.5month BP but it is perfect for a boa that size.
Again there is a lot of debate about feedeing