I visited a friend last weekend in a small town near Boise. She owns a greenhouse-herb business there. She has a number of large domed cold frames, all of which were propped open. She said she had been moving the flats under the domes, and found the weedcloth beneath covered with slugs. She has four "silky" chickens, who were looking under her arms, and they moved in and pigged out. They hung close by, waiting for her to move another flat. I think they also eat lacewings and lady beetles, unfortunately. But she says they don't seem to know that seeds are edible. They certainly do a good job in the yard, though. I don't know whether she lets them in the greenhouse. If she sees slug damage, I'm sure she would. Margaret L