Family Member Bought And Sold Livestock In Our Name, What Do We Do?

Hello, we recently found out my husbands step dad owned cows in my husbands names and sold some of them recently. There was a check of $500 written out to my husband and we were told my the sales barn it was done as a Split off check, and to my knowledge this is done so that a shareholder can have some of the funds, but also to avoid curtain taxes. My husband doesn’t own any part of the ranch, and was unaware that there were cows in his name. He wasn’t present for when they were purchased and didn’t pay or sign for them. This is something we are uncomfortable with. From what I gather it isn’t necessary illegal (the money/check) but it is a gray area due to the taxes. Since we were unaware of these assets, the cows, doesn’t that mean we would have had to declare them on our taxes every year? Can you all help me understand this and give me advice on what I should do? We did decline the check and told them to not put anything in our names.