I have mum and her pup who is 14 weeks old they play great together . but sometimes mum will snap at pup and has grabbed her to the point pup screams and  she seems to take a long time to let her go . i am not sure whether i should be jumping in or letting mum carry on . she also stands across me to stop pup getting any attention as you can see with earlier posts i have had trouble with this bitch and another one i had .My other bitch has recentely been pts with bone cancer and as i only now have these 2 i dont want to make any mistakes that may stop them getting along together . i've always worried my other bitches not getting on was my fault and i in know way want to repeat amything i may have done wrong . i've lost 2 biches in the last few months both very unexpected now i seem paranoid about every little thing any advice appreciated

Some mums can be quite rough and it can sound awful but she's not really hurting them. Generally they know what to do themselves, but I would just watch them and if you think its too rough then intervene.

I would be hesitant in doing that having done it myself to one of my dogs when I though she told the pup of too roughly. The pup then took over and the older dog thought she couldn't do anything about it. This time I let the older dog tell the new pup off and the pup is respectful to her.  

In regards to the jealously, its quite common in dogs. At the end of the day, you can't let her get away with it- you need to bond with the pup. Push her out the way and don't let her do it. But in saying that I let mine get away it all the time!