Yes, after killing a few coyotes they will eventually encroach again, and the farmer will have to kill a few more. The amount of time between the first and 2nd wave of yote territorial encroachments won't be a day. We are talking months or years. These periodic defenses of your territory from encroaching wild animals is just part of living in nature and around wild animals. Its not like you kill one and the next day another takes its place. These are temporary solutions. If someone had come up with a permanent solution that worked all of the time we wouldn't even be having this conversation.