What kind of dog is this besides cute!!

First pic is at 10 weeks they say and the other of him with his buttbin the air is him at a year and a half. I thinks he’s about as big as he’s going to get. They said that he has some Jack Russell in him for sure. I’m going to have his DNA checked or however they do that these days to see what he actually is. I think the owners were puppy mill bastards that mistreated him. He is such a sweet and very very smart dog. He learns things on his own and he loves to bin and play now. We lost our precious dog of 17 years his name was Ringo and this one is Bailey. He has filled a huge hole in our hearts. I have a mentally handicapped brother that has lived with me for over 30 years now and boy ol boy was he happy to see Bailey. He rode in his lap all the way home. We were an hour and a half back home. We rescued him and why please tell me why or how can someone be so bad to animals. I felt like cursing the previous owners out when we had him in our hands. But I just wanted him to come with us no questions asked. It was love at first site for sure. He ran into our arms. Theee people they told us that if someone didn’t come and get him that day that they were going to have to take him to the pound and have him you know what! I said well I hope you’re not there when I get there to pick him up because I’m going to punch you in the mouth for just saying that. You don’t do that to a 10 week old puppy!!! You don’t do that to any dog if you ask me!! What’s wrong with people today? Man that pissed me off bad!! They didn’t care all they wanted was the 80 bucks for him and I gladly paid it and would have paid whatever it took to save his little butt. He is so cute. A very good looking puppy / Dog. Which makes me think that they were running a puppy mill because I think he was pick of the litter and they kept him and found that they couldn’t handle another dog. Their whole back yard was dirt. Boards shoved under the fence where a bunch of dogs had been digging and man that was enough for us. I couldn’t drive to Winter Park fast enough. Anyway would like to get a clue as to what he is and when I get the results back I will post them on here to find out who was the closest. So let me know ok guys. Thanks in advance.