My two girls are very tiny also. Cutie is 4 yrs old and she only weighs around 3 pounds (btw...she's the one who thinks she's a Rottweiler). She is very healthy, strong and energetic. The vet says she is very healthy, just tiny. I want to have her fixed just in case but I am concerned about anesthesia in one so tiny. My Hannah is 7 yrs old and she only weighs in at almost 5 lbs. she is too is very healthy and happy.
