Ive had these issues aswell. Every time i get some pups, the other rays are all over them.. Ive had 2 gettn eaten and 2 that got injured, but made it. Have to take them out ASAP, but its not easy to tell when they are comming.
On the ones that got eaten, were they entirely consumed, with no trace? I ask because I'm very suspicious that there were more than 3 pups in this litter, but I found no trace of any others.