If you want to make it as low maintenance as poss with a batch of commercial cades that are destined for your freezer then you can give them cool ( not straight from the fridge cold) milk and reduce the frequency of feeds fairly early o. Many people on this site seem to advocate this no nonsense approach and appear quite content with the outcome.
I keep a rare breed and my current batch of bottle feds are 3 ewe lambs removed from a ewe who suffered nerve damage in very late pregnancy and had to be nursed, lambed and finally euthenised. I lost a ewe and incurred a vets bill but consider my self very lucky indeed to have got 3 live healthy lambs out so I want to give them the best start that I can.
It is not easy for me to go out and find a high quality ewe to replace the one I lost so the value of my sheep is greater than just financial. Also as a breeder, a bought in ewe would not be my bloodline so raising my own sheep to a high standard is important for me .At least one of these ewes will make a replacement for the ewe that I lost and the sale of the other two will cover the vets bill but only if they are all good enough.
Milk replacer and artificial colostrum is no comparison to their mums milk so for me, if warming milk and feeding 4 hourly gets them from wretched, shivering causes for concern to super big strong lambies then I'm happy to put in the time. I have a sheperdess bucket but I have decided to bottle feed this bunch through to weaning. I combine heating the milk with making a cuppa and combine the feeds with checking the pregnant ewes so it really isn't a big deal for me.
Mine take much more milk when its warm with no side effects from eating guzzling their fill with lots of tail wagging enthusiasm and are growing really well considering their shaky start so I'm with Farm vet and Crbecky on this one.
You will I imagine, get lots of advice to the contrary and I'm sure both approaches have their place. You will know which one is right for you and your lambs.