Hey, think about the aircraft carriers. The Prometheus and Daedlus can probably house 3000 sailors, maybe more than today's modern day aircraft carriers. Now, that would be about 6000 crew members and those kinds of ships are PACKED with food the last at least two years out on sea. And don't forget the Macross, it has a large grew so food was abundant. Now, seeing how advancements were made in space travel, they can grow their own food...but I'd get tired of soy burgers pretty quick since I'm not a vegetarian.
BUT! Forget about the food, think about the ammunition! And the materials for replacing the lost Valkyries! Not exactly the "Mothership" from Homeworld.