A few runny brown poops is normal. Those are usually what we call "cecal droppings", the occasional emptying of the cecal pouch near the rear of the intestinal tract. I call those bad-chocolate-pudding-poops. If you see more than half of those type of droppings, then there might be cause for concern.
In any case where you see unusual droppings, it is best to boost the bird's own immune system by providing them living bacteria. Their systems are able to digest and absorb food via two things: grit in the gizzard, and bacteria that dissolve what the gizzard didn't break down enough. Without a healthy load of bacteria, the entire digestive tract slows down and is more susceptible to *bad* bacteria as well as other pathogens like cocci.
So weird poops, give probiotics.
Common choices are plain yogurt (1 teaspoon per adult bird weekly, daily during medication with something other than cycline and mycin drugs, 1 teaspoon per six chicks weekly), acidophilus tablets or capsules (crushed onto the food or into a quickly eaten treat), or a livestock probiotic from the feedstore. Livestock probiotics must say "CFU" somewhere on the label, denoting that they contain live culture forming units of bacteria. They can also contain byproducts of fermentation, but must still contain live bacteria as well. Probios powder and paste are my favorites. Fastrack is another good one. The horse and cattle aisles have many choices.
Otherwise, to further answer your question, we'd need more info. If you can see the post second to the top in the forums, it has a list of questions that help us get a better picture of your flock's conditions so that we an more accurately answer your concerns.
