Certified seed is cleaned, close to weed free, and known germination rate. I hve used feed oats for years, it works fine. Purple bag from tractor supply works fine. Local hardware store has feed oats by me and they work fine too.
Take 50 random seeds from the bag and put in a shallow bed of soil. Each one that grows is 2%. I stopped doing this on feed oats, always was 85-95%.
Rye is better, try finding a local source. MAny times the seed rye is the same price as feed oats,