i am about to take on my new boy who is 6 month old border collie. he has been brought up ( u wont believe this!) on Bakers ADULT complete & butchers tripe. obviously im not going to keep him on this! my thought is to feed him a junior/performance type complete dry food, my other 5 are all on an adult working dog food (csj/autarky) he has no muscle at the moment, from the fact he hasnt been walked, so i will need to get him fit gradually too,

just wondering what others would feed in this situation? the rescue have put him onto burns as he had major runs when he came in,

any advice would be fantastic!

try a few different foods out and see what suits him best what ever makes his coat shine and he enjoys and no runs is the right stuff

If he is doing well on Burns, why change it? IMO at 6mths a BC doesn't need any 'extras'. In fact you may find higher protein foods send him through the roof, I know it would with mine! ;-)
Let him muscle up naturally and gradually with the introduction of exercise rather than hurrting it along with high protein food. I got a rescue collie 6 weeks ago. He was 8mths and in a similar situation. He's on All in One and has doubled his muscle already.