1)
If the people are buried, how will birds eat them?
1.
Radak, Malbim: They will eat those who were not buried due to lack of places, (Radak - or due to weariness of the buriers due to the many dead).
2)
What is the meaning of "v'Ein Macharid"?
1.
Rashi: No one will chase the birds from the corpses.