Some dogs eat their own poop. Other dogs eat other dogs poop and not their own.
To be honest, your pup should be going outside every half hour for toilet breaks. Keep an eye on him when he is in crate and if he starts sniffing and turning around he probably has to go. If you don't want him near his own poop in case he likes the taste be vigilent witih him and pick it up as soon as he does it.
It doesn't sound like he ATE it. He probably just finds this new thing in his crate rather interesting and was checking it out. He's only a baby. I doubt it could hurt him. Someone else might have other opinions though.
Pretty normal I have a 3 year old Cocker Spaniel who has a fetish for eating her own poop :vomit:. She is a puppymill rescue and our best guess is she wasent fed enough and often ate her poop cause she was still hungry. Puppies usually eat or lick their own poo for a few different reasons. The first one they witnessed their dam "cleaning up" in the whelping pen. And since the pup licked it in his crate? Right? He/she was probley just trying to do some clean up. Anouther reason is boredom. And last but not least maybe the food the pup is eating is missing a mineral that its poop contains.
Its not really dangerous I don't beleive for the puppy. But I would be wary of puppy kisses on the face just incase of worms :vomit:. I would just watch him though. This may just be a one time thing. But if it becomes a major problem there are supplements Vets can give you to put in the pups food to make his poop taste awful. There are also many home remedies you can try. But really your best bet is to do your best to keep the yard and crate clean. Even if that means scooping the poop right after it hits the ground.