If it were the Cabbage Loopers or the European or Imported Cabbage Worm you would see wee green caterpillars around the holes. But what that looks like to me is slug, or snail, damage. Control is many faceted starting with eliminating as many day time hiding places as possible. Traps, baited with stale beer, can be set out. Some report good results with strips of copper tape and others report good results with sharp substances, although many others report these wee buggers can crawl right over that material after laying down that slime trail.
There are baits made of Iron Phosphate that can be used as well, although due care in use is nece3sary since this can be harmful to children and pets.

Here is a link that might be useful: control of slugs and snails

Just my 2 cents: Sometimes you have to accept some damage in an organic garden. If you eliminate a link from the natural food chain, you may get unintended consequences. For example, those slugs are eaten by the lizards, skinks and garden snakes. If you don't allow some of those food sources in your garden the predators may move elsewhere. The slugs will eventually return in larger numbers and having no predators will overwhelm your garden causing you to purchase more packages of "slug removal". That being said, a little bit of cheap beer in a bowl goes a long way to thinning them out.

Look on the undersides of the leaves for cabbage worms and loopers and around the edges of the eaten areas for slug slime. Cut worms are also a possibility although they normally either go for really young plants right at the ground level or climb up to the tops for the youngest growth. Both slugs and cutworms are active at night, the slugs hiding in surface litter and the cutworms often digging in just under the surface by the plant stalk during the day. Cabbage loopers and green worms just eat. If you have the white or yellow little butterflies, you will have the cabbage worms. The butterflies are the adult form. There are a number of the butterfly/moth family whose larvae feed heavily on the coles.

Flowering plants to provide nectar for wasps and hornets will help control the caterpillar problems, since many of them will come to the nectar and then also hunt for the worms to feed their larvae. Do not discourage them from wandering through your coles. If you watch you may very well see one of them come flying out with a caterpillar in its grasp. Don't crowd your coles and you will make their hunting easier, and your cole harvest then also cleaner.

Thanks guys. Appreciate your help. I found slugs yesterday after rain. Removed them.