OMG! This is such a brilliant idea! What can you feed the birds? The whole mash? Can it be preserved for any amount of time? I am going to be speaking with local breweries for sure!!!
Freeze it in trash bags. My sis and bil live in NJ so they freeze it when they make a batch. It serves 2 purposes, it keeps it for me for my rare trips to NJ, and it keeps their freezer colder so when they lose power for 10 days (anyone heard of Hurricane Sandy?) the food doesn't spoil. And yes, I feed them the whole mash. Now, I feed it as a supplement, but it is similar to fermented grains, so you can do the reverse and serve it as the primary food with your layer mash as a supplemental.