Quote Originally Posted by wolfy-hound View Post
The concentrated food color is a great thing. I never tried it on rats. A dab on the head would probably work.
When I marked holdback females, I notched ears at the crawler stage. Sorry, but it didn't seem to hurt them, marked them effectively, and had no seen adverse effect. In fact, some of the last 10 rats I have are those females.
Actually I just watched a show that had lab mice in it. They were explaining about some weird regenerative mice that were bred! The lab routinely punched a small hole into the mouse ears of those that they wanted to tell apart.. Well, in these regenerative mice, the hole regenerated! Not just that it healed.. it completely closed up. I am not saying that anyone should go punching holes into their rats' ears.. I am just saying that labs do it with success apparently.