I have a mixed breed lab and she is great. She is about 60lbs and only comes to the middle of my thigh (I'm only 5' tall). We adopted her when she was 1 1/2 years old and had been abandoned in the city with a litter of pups. She gave everything for them, and when we got her, she was 35lbs (skin and bones) and had been in the shelter for 12 days. We knew just looking at her that she was ours. We took her home and she did not eat for 3 days straight. She was scared of men, trash bags, brooms, rope, and loud noises. About a week after we got her, my little cousins came over (they were 3, 4, 7, and 9 at the time) We all took her out and that's when she came out of her shell. She absolutely loves kids, and babies even more. When she got comfortable, she did go through a phase where she ate shoes, but she grew out of that and we made sure to keep shoes in closets.
We have had her for 9 years now and although she is still scared of new men at first, she warms up to them if they just leave her alone. She has also helped raise 5 litters of abandoned kittens, carrying them around and cleaning them after they ate. It took some time, but she has been the best dog we ever had. She will leave the chickens alone if you are out there, but I don't trust her alone. She completely stays clear of the goats after one of them head butted her while she was chasing them .
Here she is with our chocolate lab, Chunk, who is 80 lbs.