When chicken broth has turned brown or too dark it usually is because the chicken broth was over cooked.
Sometimes overcooking the chicken broth makes the chicken broth turn brown.
If the chicken broth tastes good, then it's not over concentrated.
If the chicken broth tastes too strong then, it may be a bit too cooked down.
Also part of the chicken broth 'tint" is that you used all dark meat. It will be a darker broth, versus the golden broth you get with using a whole chicken and carrots.
If the chicken broth is actually bad then it will smell bad but if it's just brown after cooking the chicken broth then it likely is okay to eat and use.
If the chicken broth has been frozen for the 14 days then yes you can use the frozen chicken broth after 14 days.
However if the chicken broth has been only refrigerated and has been refrigerated for 14 days then it's likely bad and should be thrown out.
Chicken broth lasts for around 4 to 5 days in the refrigerator before it goes bad and gets sour and grows bacteria.
If your chicken broth has actually gone bad then it will smell sour or have a bad taste to it.
But if the chicken broth has been in the refrigerator for 14 days then it's very likely that it's 100 percent bad either way.
I would not eat any chicken broth that has been in the refrigerator for 14 days.
But if the chicken broth has been frozen for those 14 days then it would still be good and safe to eat or drink.
Chicken broth that has gone bad will have a bad smell to it and may have mold in it as well.
If you notice any bad smells to the chicken broth or mold then throw it out.