Go for it. I strongly encourage you to always try new things in you garden and see what works. With that being said I would not recommend planting gourds directly in manure unless it is well decomposed because that would kill the seedling. You could try planting it in some potting soil in the straw bale and put manure in other places around the bale just not directly on the seed. Also, for best results, you should probably try and use a straw bale that is falling apart and decomposing (maybe one that has been out in the rain for a season) so that more nutrients are availble to whatever seeds might grow.

Can I ask why you don't want them in your vegetable garden? Even if you plant it in a hay bale the gourds could still take over a lot of area if they aren't on a trellis. If you just don't want them in your garden you might want to try just planting them in random places in your yard I have had excellent results with gourds I plant in a spot on the lawn near a fence or something to climb on.

Thanks Weirdtv, I was thinking of the straw bales because they vine so much but am now thinking of putting a couple of hog panels in and letting my squash, gourds and melons vine up them instead. I will need to support the fruit somehow, maybe panty hose? Thanks again, Lauren