
This is normal bitch behaviour at this age, and the short feeds too.
How may meals a day are the pups getting?
Are they being fed to appetite so that there is always some left over for Mum to Polish off?
Personally I would have them on a soaked complete dry food too, as many new owners are likely to feed dry.
As for supplementary Milk I continue this unless they pups motions start to soften, which often occurs when Mum starts weaning in earnest, as this signals the end of them tolerating milk well.
It is not unusual for them to vocally object to Mum withdrawing/reducing milk-bar privileges.
After her milk has dried up somewhat and they have accepted this she will return to take more interest in their education, so let her dictate how much she wants to be with them and only keep her away while they have their meals.
As for Water keep it available and they will drink if they need it.