Can mothers give birth to two cats at different times? (i.e. need runt info)

Hi this feral cat (which we are desperately trying to catch and spay) has kittens in our backyard and we try to catch them and adopt them out. We had one litter of five and most kittens were similarly sized (some smaller etc.) and healthy. Now this litter is only of two. One is HUGE and one is tiny.... really tiny like a mouse.... but it runs around and tries to eat solid food. It also still has bluish eyes and the other one doesn't. Can a cat drop and fertilize two eggs at two different times? I.E. could one be younger than the other? That is what it looks like if that is possible. Or could one have had shorter justation and be "premature"? Just curious because if its not that this is an EXTREME runt and we're worried it may have alot of health problems.

Yes. It is not common, but it can and does happen.