I think that the arrangement of the animals in listening the Old Major is really important. The pigs sit right in front, so that they can hear everything. It is also important to note that the pigs are hanging on Old Major's every word. In their placement in the front, as close as one can get to Old Major, it is evident that the pigs see this as an opportunity to gain knowledge and insight into something that is going to translate into power for them. It is apparent that they sense and know this. Accordingly, their placement in the front is to reflect this premonition, and a bit of foreshadowing on Orwell's part. The fact that the three dogs, Bluebell, Jessie, and Pincher sit in front of the pigs, almost escorting them is also significant because it is going to reflect how the dogs are in protection of the pigs, especially Napoleon. This becomes painfully apparent in Chapter 7. The dogs are presented as almost escorts in how they lead the pigs, and will become the "muscle" of the operation under Napoleon's rule. The other animals' arrangement like the sheep, cows, pigeons and hens are all peripheral in their arrangement in listening to Old Major's message. This is reflective of how they have a role in the farm to come, but it is a tangential one. Bringing in the back and demonstrating concern for the other, smaller animals is Boxer and Clover. This is reflective of how both cart- horses truly believe in the animals' well being, something that is going to end up being manipulated by those in the position of power as the novel progresses.