I seriously hope you are not just feeding them dog treats as a main diet.

Do you know how old your rats are? The pink-eyed white looks a bit thin and poofed out, so he/she may be ill or stressed. If they are under 4-5 months, they need to be separated and should not have babies until they are of the proper weight and age.

Look under my sticky for a Rat Food mix. It is cheap and will give your rats all they need(unlike stupid pet store mixes that contain dried corn and other fillers that have no nutrients). If you don't feed them properly, which includes feeding a good lab block(Mazuri, Harlan Teklad, etc)in addition to the food mix I provided a recipe for, they won't be healthy enough to even produce a litter.

Also, rats shouldn't be kept on newspaper. They need bedding such as aspen(no pine or cedar...), carefresh or something similar to help soak up their urine and to give them something to do. Rats and mice are burrowers by nature, and it is only right to let them do what they were made to do. You can get a HUGE bag of aspen bedding for around $9 at Tractor Supply Co. You can also get it at most pet stores.