Moving pup from puppy food to adult food

[ChickensThinkYouCanGetStuffed]

Jasper will be 6 months old at Christmas. He's still having 3 meals a day, although has slightly less food at lunchtime now and I generally put it in his tug-a-jug or kong. He has approx. 200g of burns mini bites spread across these meals. So I've been looking at the adult food, and it seems that when he moves on to it he will be having approx. half the amount of food he has now. Is that right? And won't he be hungry? He is always very quick to wolf down his food now, and I can feel his ribs very easily. Should I cut out the lunchtime feed when I switch him? And how do I go about switching him? Thanks.

We have a springer and we were advised to keep her on puppy food until about 7-8months.

She is 8 months now but been on High Energy Lamb for the past month to try and get a bit of weight on her bony frame We have been advised to keep her on that as she is doing ok on it and she can stay on it for a while yet. That said I'm thinking of moving her to a raw diet.

Depends on the breed, but 6 months might be a little young.
Generally yes, they will eat a little less as an adult, because they stop growing, but if your pup is not yet full grown, you'll probably have to keep increasing adult food allowance.
Best to start him on what they recommend, and then adjust upwards to make sure the dog is at a healthy weight.
You want to be able to feel the ribs without too much effort, but not see them, and there should be a waist on the dog. (Size and shape of waist rather breed dependent.)
In terms of switching over, best to do it over about 5 days. So you just take off 20% of puppy food and add 20% of adult food (using the weights listed for each food independently). Go up in 20% increments, and dog should be fine.
You might find a bit of squishyness in crap for a few days, but that should should settle down in a week. If it doesn't the adult food may not be suitable for your dog (some just aren't) and so it's worth just buying a small bag to start off with.

Our puppy is eight and a half months old and is still on two meals a day. When do you switch to one meal a day? We feed him at lunchtime 12.30 and 6o clock. He sits beside his bowl waiting for his food but doesn't really bark.