Final answer:
The best transition to complete the sentence is 'However,' as it appropriately contrasts the positive aspect of owning a chicken coop with the negative viewpoint of neighbors.
Step-by-step explanation:
The appropriate transition to complete the given sentence is one that contrasts the positive aspect of maintaining a residential chicken coop with the negative viewpoint of the neighbors. The sentence before the blank expresses a positive view about chicken coops, while the sentence after the blank brings up negative consequences. Therefore, a contrasting transition like 'However', would fit best to properly convey the shift in perspective.