Lisa's the serious embrologist in the clan, but this dog pic would be remarkably close to true for an embryo. Weather chicken, dog or human, it's pretty much the same drill: ball of cells becomes flat disk of cells becomes tube becomes twisted tube. It's how we moved past worm form (not that there's anything wrong with worm form, but it's easier to overrun the planet with appropriately long and twisted intestines).
Here's a cool yolk to gastrointestinal tract animation if one is into that.
Warning - embryology mini-talk ahead.
Lisa's the serious embrologist in the clan, but this dog pic would be remarkably close to true for an embryo. Weather chicken, dog or human, it's pretty much the same drill: ball of cells becomes flat disk of cells becomes tube becomes twisted tube. It's how we moved past worm form (not that there's anything wrong with worm form, but it's easier to overrun the planet with appropriately long and twisted intestines).
Here's a cool yolk to gastrointestinal tract animation if one is into that.
Embryology GI tract animation
This pooch sorta looks like Frosty dog.