In my case, the chickens are harder to care for than the cat, but easier than the dogs.
The chickens live in runs 24/7 since they can't free-range where I live, so there's no letting them out and putting them away every day. I can fill up their food and water and they'll be good to go for a few days if needed. Takes me about 15 minutes every day to check on everyone, collect eggs, make sure they've got food and water, and that's it.
I do have an unusually easy to care for cat so I don't know, maybe other cats are harder to care for than chickens. My boy is 12 years old so he sleeps most of the time and doesn't want anything from me except food. 
My dogs are more work than the chickens but I think that's probably common, especially if you've got a smaller flock. One of my dogs is very young and high-strung, and the other is on a weight loss plan, so they need daily walks and playtime in the house. Plus the dogs need regular vet visits, vaccines, etc. that chickens may not need often.