My 6 year old standard schnoodle doesn't come when I call him while we are out walking. If he sees a cat, chicken, or almost any small animal he will purse it and ignore my come command. At home or in close quarters he is obedient. There have been days when I have been late for work because he has ran off. I can't run him on the leash so I need to be able to let him run on his own and return to me when called. Thanks in advance for your advice.