I think doggy smell is often food related, what do you feed them on at the moment?
My dogs are fed on Burns (a complete dry food containing, in our case chicken, rice and peas, but there are other varieties available) because it is simple to digest and isn't crammed full of fake gravy, preservatives and colourings.
It is also not produced by any of the major pet food manufacturers (eg pedigree) who do some truly awful things to dogs and cats when testing out different types of food. It is because of their cruelty that I refuse to buy their products.
Have your dogs had their anal glands emptied? One use of the glands is to eliminate waste from their bodies and if they're full it points to both too much waste in their systems, and possible a contributor to their smell! The waste can come from food which is too processed for their systems to cope with.
My parents had an elderly, rescued golden retriever who stank! We changed her onto Burns and quite quickly she lost her scent ... it made life much, much more pleasant.
Their website is www.burnspet.co.uk