I wouldn't ever try to hand feed a rat pup really, it's very hard and around the clock work. They cannot regulate their own temperature yet and at this age they still very much need the Mom. Not sure where you read that but it's a nightmare and I really beleive your just prolonng their death while doing this. Keep in mind Mom rat may be doing it because she senses something wrong. As much as it sucks, LEAVE IT BE. Like you've already been told, calm her down and place her somewhere quite and dark. Try a warmer area too. This way if she does leave the nest while freaking out the pups won't be cold and she won't need to spend as much time on them. She might just be an easily agitated Mother, I personally don't agree with breeding rats like that.