Keeping hay bales green?

The long answer: Technically speaking there are 3 main processes that cause hay put in at proper moisture to discolor. 1. Sunlight causing a general denaturing of beta carotine and a general solar bleaching effect (radiational effect on the chlorophyll). 2. Evaporation of water, dew forms on the hay in the barn the same as outside, unless the barn allows for NO air exchange. It evaporates as the air temperature rises. Depth of bleaching is determined by amount of water and the number of evaporations that take place. 3. Oxidation, unless the barn is vac. sealed oxygen will form oxides with the chlorphyll compounds present on the surface and form complex magnessium oxides. Results are the same, outside of exposed bales turns brown. Reducing these 3 processes (middle of a stack) reduces the effect. Only time I can keep the outsides looking pretty is when I film wrap hay below 14% moisture (above 14% and below silage moisture water leaches to the surface and forms a slimey brown layer). Going to try spraying outsides with propionic acid to see what this does for film wrapped dry hay. Alos had some good silage last year that went in above 50% moisture, came out real pretty.

When I'm selling barn stored squares. I bring the customer in the barn, grab a bale and always flip it 'pretty' side up to show them. Say something to the effect 'of course the outside of the stacks will be bleached in a quarter inch or so'.

I have round bales that i put up in the barn that was a nice green color when baled the outside of the bale is a golden brown but less then an 1/4 of an inch in side the bale is still green.