Not sure if lawn grass grows year round where you live, if it does, this might be harder to visualize.
So the corn was harvested last October, and just a few days after that, this barley was planted. It germinated and grew to a height of about 3 inches before the cold set in and it went dormant, much like a bluegrass or fescue lawn grass will do in a cold climate. March rolls around, and about mid march, it starts to grow, slowly but it grows (much like my lawn). The last 3 weeks have been pretty good growing conditions and it grew to the height you saw, and the grain stalk was just starting to mature.
You have to realize this is planted primarily for soil retention. Usually the county, state or feds will pay for the seed, so most farmers will take advantage of it. Its use as a feed is secondary, as it has a much lower calorie content then crops grown for that purpose. As stated, it is much closer to hay then grain!
Just to give you an idea, here is a shot of the size of the barley a month ago, the field behind the wood rounds...
Wow, you do things different in your parts. We harvest barley in middle to late summer after it has turned yellow. We use a combine that collects the grain and shoots the chaff out the back. I would have thought you were knocking alfalfa down for hay based on the technique being used.
This barley is not being harvested for the grain, it is being harvested to turn into silage to feed cattle and dairy cows. So they need it green with some moisture.
Still... how does it grow so fast? Freezing to thaw in the PNW doesn't grow anything.