Very normal for them to be frightened by new things. Might take a day or two to realize it won't eat them, so just give it time. One of them will get brave enough to drink.I don’t have any milk jugs at the moment, but I doubt they’ll even think of going near the jug as they even get scared and avoid any new container or object I put in their container
You have been given a lot of good advice here. I think your improvised feed sounded great. Maybe add a little more plant material... some chopped broccoli or kale, even grass. They need small pebbles (large sand) in their crop to help digest all the food, so sprinkle some in their pen. They will eat what they need.
Are you planning on keeping them?