If there was an agreement, even an oral (unwritten one) that you would be paid for caring for his goats and he has not paid you, could sue him for breach of contract, or violating the agreement between you: if you did your part (cared for the goats), he is obligated to do his part (pay you). You could also sue (a second ground or reason to sue) based on "unjust enrichment": he may not get the benefit of your services without paying for them. You may sue for the agreed upon amount; or if no amount was specifically agreed to, for the fair market value of your services (what he'd have to pay to hire someone, typically, to do this). Suing in small claims court, as your own attorney to save legal costs, may be a good option. You can get instructions on how to do this from your county's small claims court.