Yes sorry I remember now, who Shadow is!

Well, I know opinons will vary here, but my method would be to teach a reliable Leave, using food to start.
Food in clenched fist, dog tries to get but can't. When dog sits back and looks at you, say "Take it" and open fist. Keep donig this until dog shows understanding, then start to use the word "Leave".
Start to then generalise this to say, toys so you start to have some control over the chase instsinct.
Use 2 toys, one very exciting and one not so. Have dog on long line, and harness. Throw boring toy boringly and say "leave" and when S. obeys, immediately play/throw him the exciting toy. Soon he should start to respond on the word whatever he is chasing.
Gradually build it up over months to Leave in all sorts of situations.
It's hard work and means lots of dedication, but if you enjoy traininig can also be good fun!
HOwever, if he chases them a lot now, you will need to stop this for a while or the training won't work so well.
If the worst comes to it try a MasterPlus collar, which is a remote citrus spray, and then give an alternative behavour such as a recall or something.
Just a few ideas anyway, hope you manage to sort it and can relax with Shadow!!

LIndsay