Pasty butt or umbilical cord?

[sbult]

We just got 5 baby chicks. This chick had a weird brownish color thing hanging from her backside (photo attached). We read about pasty butt and rinsed her bottom in warm water, then dried her off with some paper towel, and then applied vaseline and returned her to the brooder with a heat lamp. She pecked at her butt and one other chick pecked at her butt as well. Now we are not sure if it is/was pasty butt or if we washed her umbilical cord. We are worried we hurt her bowels. She is laying down now with the other chicks. Is there something we should do or just let her be?

 

[cottontail farm]

Is the dark area poo before you washed it or is there a hole there? Pasty butt is just caked on poop, Did it seem like it washed off completely?

 

[sbult]

Is the dark area poo before you washed it or is there a hole there? Pasty butt is just caked on poop, Did it seem like it washed off completely?

Some poo washed away with the water but there is still something attached. We are thinking it is the umbilical cord. I attached a photo of what it looked like before washing. The photo attached to the original post is after washing.