I agree with Corinna, most 'farmers' will not put more money into an animal than what they can get out of it. It is not practical to them to seek medical attention for a farm dog, goat, chicken, etc. Usually farmers will seek medical attention for sick cows, if they get money out of them or if it will cost more to replace the cow.

Why don't they let the horse out with the cows? It sounds like the property is big enough, if they bury all their animals out there.

The dogs concern me. If the elderly one has no teeth, it probably can't eat much. And the 'mean' one...if the uncle goes in the morning, and the dad goes in the evening, and it takes both to feed them, how often does it really get fed?

If you are truely concerned, I would at least try to ride by the place. See for yourself, snap some pictures if the place is concerning. Then contact an animal control agent.