In all of the feeding miracles (Matthew 14:13-21, Matthew 15:32-16:10, Mark 6:31-44, Mark 8:1-9, Luke 9:10-17 and John 6:5-15) would it have been possible that the extra bread and fish did not get miraculously created? Instead since the crowd was all sitting and saw Jesus break the bread and fish that they also decided to break up their own bread and fish that they might have had with them to have fed everyone there?
This is not possible, unless (in the first feast, feeding the five thousand) the disciples made a foolish assumption:
Mark 6:36: Send them away, that they may go into the country round about, and into the villages, and buy themselves bread: for they have nothing to eat.
From that verse, we ought to assume the crowd really did have nothing to eat. Even less likely would be that Jesus made the same false assumption in the second feast (feeding the four thousand):
Mark 8:2-3: I have compassion on the multitude, because they have now been with me three days, and have nothing to eat: And if I send them away fasting to their own houses, they will faint by the way: for divers of them came from far.
The options are then limited: either the bread and fish were created miraculously, or the gospel author was misinformed about these events. The texts of the three synoptic gospels often agree very closely in wording and order, both in quotations and in narration. Most scholars ascribe this to documentary dependence meaning that, in the absence of a miracle, only one evangelist (presumably the author of Mark) need have been misinformed.