[landroverroy]

E-numbers?!!  Why would a dog care what colour it's food is

Shakes head sadly...

If pet food producers made food that appealed to the pets, Felix' best-selling flavour would be 'Mouse' and Pal's 'Smelly old bone with added fox poo'

Exactly
The dogs couldn't give a stuff what colour it is but a range of colours looks more appealing to the owners. The green and red and yellowy bits (+ accompanying E numbers) gives the illusion of healthy meat and veg, and disguises the fact that it is in reality some poor quality by-product sprayed with mechanically derived meat slurry so it smells right.  
 

[Old Shep]

Yes -  the worst dog food you can feed your dog is the likes of Bakers with all the colourings - it sends especially border collies sky high.  The protein % is not so simple as source is also important.  I feed raw which looks high in protein % but does calm dogs down ( I foster rescues so had plenty of chance to test it).  I wonder if its all the beaks and claws that make up the protein in kibble that has the "hyper" effect.

[Foobar]

No E numbers or mechanically derived rubbish in the food I use anyway, nor any cereals.  Diet isn't the issue in this case, he is very calm in all other circumstances, he just has a very high work drive I think.

[SallyintNorth]

Then I'd just try to do lots of training where there are other dogs working sheep, and he only gets taken to sheep when he's calm - but he does get taken to the sheep when he is calm.  If he's a nightmare he gets put somewhere where he can't even see the sheep.   When I say 'lots of training', keep the sessions fairly short and give him time to reflect between. 

Both my dogs are now reasonably good at staying on the quad bike, almost no matter what anyone or any other dog is doing with sheep - but if he thinks whoever's doing the job is making a mess of it, Skip sticks his nose right in my ear and gives me a commentary.  If my hat is over my ears he pushes that out of the way first. 

Dot sits on the bike and watches and thinks.  When it's her turn, she'll have worked out how to do the job her way - and it's often better than what she's been watching.

[nutterly_uts]

Might be worth working on him at his threshold (find the distance away from sheep he can cope and listen to you nicely and remain calm), and in time, bring him slowly and slowly closer until he is doing that next to the sheep - then going into the field, coming back out to his new threshold again if he needs it. It won't take him long being a smart collie to work out calm and steady gets him to play with sheepies 

[Marches Farmer]

He's still young. Mine was a hyperactive hooligan until he went to live with Alison Smith for six weeks.  Now he's 4 and has calmed down beautifully.