My 10 Khaki Campbell ducklings are just over 1 month old and currently living outside in a coop with enclosed yard. I would like to allow them to free range, but I'm nervous about getting them to go back into their yard and coop at the end of the day. Right now, they still won't go into their coop easily- I have to trap them in a corner of the yard and then pick them up one at a time and place them on the ramp. Once they are on the ramp they almost always go into the coop. They want me to be around,but not closer than about 8 feet away. How can I make sure they won't run all over my 1/2 acre property instead of going into their yard?