Where do you live? What kinds of raspberry do you have (varieties?)? What
kind of soil do you have? Are there any nearby plants suffering the same
type of problem (stunted growth, yellowing leaves, poor fruit production)?

i live in the midwest by chicago... and the nearby plants seem to be
thriving.... all the fruit trees produce a fairly large amount of fruit, the
climbing rose next to the raspberry looks as though King Kong could smell it,
and the climatis is growing very well....
as for variety... the plants have been there for 10 yrs... in when we bought
the home and still produce a large amount fo fruit, just very small berries....
soil is well drained but i have never *improved the soil* but it does get an
occassional *miracle grow* watering and food.....