Not sure about Willys. Where in Sweden do you live? I have plenty good farmer sources. But Ica and Hemköp are good. The best is probably City gross as they are the only supermarket to butcher and package all their stuff directly in the store wich sounds like a huge bonus to me.

Sweden doesnt use vaccines or antibiotic drugs on their animals. + Meat in popular markets like ICA and Hemköp have fairly good quality suppliers. Its worse in other countries tho.