I am having the same problem with my gunias, besides them picking at the layers, They travel over a mile, and eat produce. I orginally purchased them for organic gardening. Someone forgot to mention besides eating the pests they really like tomatoes, more so than the turkeys and layers.
I will say now that I moved them in the barn for the winter with the layers thay have settled down. I also took out two roosters (had to many). They are a little nicer. But on a nice day I let everyboby out to enjoy the sun and the guines still wondered to the busy road that is so far from their roasting area.
Anyhow when can you butcher before they are only soup and stew material? Mine are 6 months old.
flock-
14-araucana, 38- iza browns, 4 black australorp, 4-buff orphanton, 5-guineas, 8-speckled sussex, 6-partiage rock, 3- RIreds, 5-white rocks, 5-barred rocks!