That is a very beautiful healthy looking umbilical area actually. This is perfectly normal and what it's supposed to look like. It will heal closed. The concerns would be prominent bulging yellow bloody fatty looking material, which would be the yolk the chick is supposed to fully absorb before hatching, oozing, uncontrollable bleeding, etc. The string looking thing hanging out is just the umbilical cord.. Also, how long since hatch did you treat the curdled foot? Minutes? Hours? Treating it wont hurt regardless, but it can sometimes be normal for newly hatched chicks to take awhile to fully extend their toes without something actually being wrong or abnormal.