I have several clusters of rhubarb stalks very close to each other, and the larger leaves are killing (yellow, but strong) the leaves on the smaller stalks. Should I pick some of the larger stalks so that the smaller stalks can comfortably grow?
Assuming these leaves are the lower and thus larger of the leaves of your rhubarb, this is totally normal. Using sharp pruning shears cut those leaves off as close to the ground as possible. Are you Fertilizing at all? Nitrogen is a mobile chemical in plants. Where there is too little Nitrogen, the Nitrogen the plant has in its own cells gets transferred to the new leaves, leaving the lower, larger, possibly not doing their job to make food for the plant because they are shaded by other leaves? leaving the lower leaves deficit of nitrogen and thus not able to do any photosynthesis. The plant itself gets rid of leaves that do not hold up their end of the deal, making more food than it takes to support that one leaf.
Also, prune off any flowers or reproductive buds on your rhubarb. You do not need to be making seed. This puts more chemistry that happens to be mobile and energy into the plant. Unless of course you are a rhubarb seed producer?
Use a simple balanced fertilizer at half the recommended directions. You want higher nitrogen than phosphorous or potassium to push vegetative growth, leaves!