When do you step in to help the baby runt rabbit?

You should step in to help a baby runt rabbit if it is noticeably weaker than its siblings, not gaining weight, or if it appears lethargic and is struggling to compete for food. If the mother is neglecting it or if the runt is cold or unresponsive, immediate intervention is necessary. However, if the mother is caring for all her young and the runt is simply smaller, it’s best to let nature take its course, as she may know how to manage her litter. Always consult a wildlife rehabilitator for guidance in such situations.