I have a Soma Lucas front rack and I sometimes carry 20 lbs. on it. It's rated for 22 lbs. Carrying 20 lbs. up there isn't ideal, but it can be done. Would be a little better with a low trail fork, I think. You want to keep the weight as close to the steering axis as possible.
https://www.somafabshop.com/shop/pro...k-lucas-3-4817
Before you carry a live dog up there I'd practice carrying 20 lbs. of inert weight first.