Is this normal poop?

[Ktewes]

I have 2 six week old chicks that have foamy poop. They do have access to dirt and the outdoors so I don’t know if this is a normal transition for them now that they are not just on starter feed. They have 24/7 access to their feed and grit. They are very active and eat well. I just have no idea if it’s normal. First time chick owner.