Some people say they have done it successfully, and others say they busted. I have never done it, but I think it is possible. Ensure you have a good seal with the cap, and let them sit in a cooler in case the do blow. Try it with one or two and let us know what happens
Some also say that shattering glass under pressure can maim, blind, or kill loved ones, small children and animals, and/or yourself. All of my growlers say right on the growler that they will not hold pressure. Do you really want to risk bodily injury, not to mention a 1/2 gallon of brew, trying to ferment in a growler??
Go dumpster diving behind your local bar or at your local recycling center and get more bottles. Everyone wins.