Busy chickens working for scratch

Often I wonder if there is something else I can do, than just throwing out a handful of scratch. It didn’t take any time, and I do mean ANY time at all for them to understand this concept. I do recommend that you try various sizes of holes in different bottles to find what works best. I feel these are a bit too large and that I have too many holes, so my next iteration will have less holes and a wee bit smaller.