Source for forage type mulberries?

I have been trying to find a source for forage type mulberries online but haven't had much luck.   Most of what I have found are fruit type.    Even the places that sell silk worms don't seem to sell the mulberries trees they use for forage.   Preferably, I'd like a type that also has good tasting leaves for human food as well.    I've already transplanted some (presumably) black mulberries there were growing wild but I'd really like to have some with improved forage production capabilities.    

Can anyone point me in the right direction?  

Thank you!

What part of the world are you in?  Richters Herbs sells lovely Mulberry trees (usually 3 or 4 different types), but only in Canada and only at some times of the year.

Check with your state dept of forestry. We can get them for $ 0.50 a tree! I know of no serious difference between forage and fruiting mulberry, unless you are interested in paper mulberry or a related species.