How many milk feeds do they have. Are they drinking plenty of water, watch they're intake for the next few days, they should be drinking water well by now. Change it often. Take them out one morning BEFORE that bottle and take them for a graze. Drop that bottle. Every so many days, increase the grazing and down the bottles. Our stopped bottles at this age. Remember that they're rumen starts working at about a month too.
The key is rationing IMHO, giving grass/milk/creep the space and time to digest with out one over doing the other. The hay which is a constant still is the buffer, not enough fibre, scours we find. . Don't put lots of creep down, let them have they're quota and put they're hay down. Ours were kept housed but free to roam yard at night, and out in day so I had a tight rein/eye on they're intake. They're now normal sheep, still daft as brushes. We have added some non thriving flock lambs to they're little crew and they do look potty, but are bright, eating well and wormed etc, it can take time for them to look more pleasing to the eye.
If you gonna keep a feed I'd keep the night one, just before bedtime. Good luck x