Very much. They love young shoots and blossoms as well as some of the veggies.
Cage around the plants to keep them protected until they're big enough to withstand some chicken munching. Once the plants are mature a little bit of chicken munching can be good. Young... they can eat your entire crop before they ever have a chance.
I never had much of a problem but I have had a big garden - chickens do go for slugs first, what I have always found adorable is they will hang out where I'm digging and eat all the worms. They like scratching in the dirt more than eating the veges.
For baby plants, keep them out. Or keep them locked in their run till baby plants are bigger. I have had limited success with bamboo stakes stuck up out of the ground in annoying places.
The less space chickens have to roam, the more focussed on your vegetable garden they will become and the worse it will be decimated.