I let mine out everyday, and now even when we go out they are free ranging.
We have two large dogs and three cats, who don't bother the chickens.
For the first two months I kept them in their run, which is spacious, and whilst they were still small I took my dogs in on their leads and made them sit and just watch the chickens, I did this several times, and I think is paid off, because now the chickens will sit in the shade next to the dogs and even jump on the dogs back pecking off the insects. andf there is no problem.
The cats would jump into their run when the chickens were small, and this was a concern, but I would just wait and watch what happend, and nothing did, I think the cats came to realise (because they would see me with the chicks) that they were all part of the family. They do stalk occasionally but never even try to catch one. One of my cats thinks he is a chicken-cat and will herd the chickens.
We have preadtors here, but the dogs tend to keep them away.
So yes I feel very confident in leaving my chicks to roam all day, they usually go to roost about 5.30 with a little encouragement, because I am sure they would stay out all night if they could.
Anyhow that has been my experience hope it helps.