Well, it depends entirely on the contract between the farmer and the reseller. If the contract states you get the retail price minus 5% and I lie to you about the retail price, certainly this is fraud. But if the contract states you get $X/pound, and that's exactly what I pay you, the retail price never enters into it.
If later on the farmer complains that they were paid according to the contract terms, but their meat is retailing for a higher markup than they expected because of its enticing packaging, I don't see how the farmer is entitled to any relief on that.
If later on the farmer complains that they were paid according to the contract terms, but their meat is retailing for a higher markup than they expected because of its enticing packaging, I don't see how the farmer is entitled to any relief on that.