That's good that all went well, as for the dog rounding them up, I may be wrong but it could be a sign of him/her protecting them.
The farm I bought my chickens from the man there had a German Shepard and he told me that it acts as a guard dog to the chickens.
Could be good if the dog is doing...
Don't overdo it with treats by the way, a few now and again is fine.
If they are jumping high and even flying you could clip the wings, there is a thread on here somewhere about that plus a few YouTube videos on how to do it.
Don't worry it doesn't hurt the chickens, it's like cutting your...
Some people entice them back in by giving them a treat, I never had to do that but it can work.
On a side issue about giving treats, when they see me they come running thinking I have something nice for them, sometimes I have sometimes not but they still come running lol.
You may see them...
I kept my hens in for 3 days when I first got them, you obviously know why, but if not it is to let them know where home and safety is plus where to sleep lol.
The first day of letting them free range I had to chase them in the coop, but I should have waited because the next day I left it a bit...