I had an old cocker and she started to smell for about the age of 2 yrs. I couldn't distinguish where it was coming from at first, but it was her coat. I had to bath her regularly because of it. Cockers can get a condition, which I believe Bonnie had called seborrhoea. The oily type produces too much oil from the sebaceous glands and gives the coat a greasy appearance resulting in the doggy odour. Anti seborrhoeic shampoos such as selenium sulphide, coal tar etc used frequently can help.