I believe a lot depends upon how you're going to raise them. I raise 25-30 twice a year in a 8x8x2 pvc pen. I block a 4x4 section off to use as a brooder then remove the partitions once they are a little bigger (around 2.5-3 weeks old). At about 4 weeks I left up one side so they can go in and out and freerange around the yard. I also only feed fermented feed twice a day, one in the morning and again in the evening. When I feed in the evening they all run into the pin and I simply lower it back to the ground, securing them for the evening. For me, this size works well with this many chicks. Good Luck.