Your body is giving you plenty of signals…..it’s up to you to respond correctly. If you’re cutting down on one activity, please don’t try to replace it with something else. With your small farm, you are getting plenty of good exercise there. You likely don’t need any additional formal exercises at this point. And, it’s still important to watch the level of home chores as well. When you have these pains, it’s your body’s message to you that it’s not ready for that level of activity just yet.
Many times people who are seeing a physical therapist do so only 2 or 3 days a week. I suspect you are out doing your farm chores on a daily basis. Your knee does not have time to rest and recovery in between these workouts. And, no matter how it may feel to you, this type of walking, bending, lifting, etc. over uneven ground can be quite punishing to a new knee. If your knee hurts, that’s the signal for at least one day off from any exercise. It is a balance and everyone overdoes things now and then. Just keep trying to keep those overdoing days to a minimum.