Hi there.
Are these spots drops of liquid? My advice would be to try and figure out if this is blood in urine or not, as that would need to be a real health concern.
This is the method we use to get a urine sample from a rat:
Find a large plastic tub/container with a lid and ventilation that you can safely leave them in alone for about 10-15 minutes or until they wee in it. You can then have a close look at the urine and see if it looks red or not. Even better still, you can buy urine dipsticks (or multistix) which test the urine for blood, protein, glucose (and other things) even in microscopic amounts. If your rat has blood in its urine it would be good to try and get them to a vet, and tell them about anything that showed up on the dipstick.
If the urine is clear, then perhaps something else is causing it but in the photo it looks like small puddles of red liquid.
I notice this post is almost a week old - how are the rats doing?