if my 6 month old aussie is 20 pounds now, how big do you think he will get?

Question

i got him at the pound and he has been neglected and not properly fed. any guesses? what do you estimate his maximum weight/height will be?

Answer 1

Do you know how large his parent are? That is usually a good indicator of how large the pup will be. Also if you run your finger along his rib, the part where it starts to go under his belly. If there is still a knot at that point (a growth plate area) he's still going to grow some more. If it's completely smooth, he's almost finished growing.
Most Aussies weight about 50-65 lbs at full growth. At a year they tend to reach full height, but males tend to fill out till about 2 years. Good Luck