Styrofoam fruit box planted with young picking lettuces.  These boxes make excellent low cost planter boxes.

Note the crumbling sections on the edges and the bottom of the box.  These were caused by chickens pecking at it.  I have found that all types of chickens will readily eat styrofoam, so if you have chickens then it is a good idea to keep any styrofoam material where they can't get at it.