I am aware that maybe we should have posted this in another location but I am totally freaking out and need advise right away. Our Star is 5 1/2 months old and despite what the breeder told us she appears to be on the smaller side (2 1/2 pounds). I've done several searches here and am a little bit overwelmed. I am looking for a flea and heartworm prevention for little ones. I have found several in large weight ranges but would love your input on any that you use for smaller babies. Please help