Blas poop- new to me flock

[Jeanboo]

Hi there. So I'm not a new chicken owner, but I lost my entire flock in October to a mink. Yesterday I got a flock from somebody consisting of 10 hens and one rooster. They're doing well adjusting well. Anyways today I noticed this black semi runny poop. Not sure if it's Cecil poop? I thought that was kinda tarry? Anyways just looking for thoughts.

 

[Wyorp Rock]

Looks like Cecal poop which can range from very dark to light.
How is behavior?
I would just observe over the course of a few days, see how they all act. If you have a bird that is lethargic, not eating well, etc. then consider taking a sample for testing of worms and/or Coccidiosis.