I've not noticed any increase in hay consumption with the switch to Fodder. I have noticed a decrease in water consumption, but this is to be expected. It is nice not to have to buy pellets any longer and I take some comfort in the fact that I really do know what I'm feeding (it's pretty hard to know for sure what's in pellets).
I only let my Fodder go for 6 days. I've not had any serious mold issues, but if it shows up at all, it's between day 5 and 6. Part of the reason for letting it go a bit longer is it's easier to feed. The root mat doesn't really take hold until about day five. There's also about 2 1/2" of growth during these last two days. While some of this is water, some of it is also living matter, gleaned from water, air, and light.
We all know spring grass gives maximum production, yet it is extremely high in water. So high, in fact, that it can cause metabolic problems such as grass tetany. So why, with such low dry matter, would these increases happen? All I can figure out is that the whole is greater than the sum of its parts somehow. That there is something in lush, new growth that either isn't noticed or is destroyed by the very act of measurement.
I accept the fact that all of these nutritional recommendations out there are just guesses. There are so many things we don't understand about living bodies. The problem comes in when we ignore the fact that our knowledge is limited and try to apply it as if it weren't. You then get the "one size fits all" solutions of industrial agriculture, that often do as much or more harm than good or only prove to be a short term solution. Fodder is a great feed supplement, but it is only one thing. I try to get weedy hay since it tells me that it probably wasn't sprayed with poison much and contains a good variety of plants. I also feed trimmings and scraps for variety. I probably don't get the production of a commercial rabbitry on pure pellets, but I don't spend much and I'm happy with that.