Winter and Spring barley just refers to when it's planted. It can be grown year round, but prefers to grow in cooler temps (though not too cold).
I wouldn't suggest using feed barley for homemade malt. It's very high in protein and has high extract potential, but it doesn't malt very well in the home enviornment... You should really stick to brewers malting grade barley if you plan on trying to malt your own.