Though both my pups are still very young, Mindy was 6 months and very much bonded with me, when I bought Heidi. I made sure I didn't upset or change Mindy's routine in any way, I kept Heidi in pen with a soft kennel, I knew there would be a bit of Jealousy from Mindy, which there was when I patted or picked up Heidi, and they had supervised playtimes together.
We also did this with previous dogs, when we had 9 year old heeler and bought a border collie pup, (both died of old age) after a few weeks, they both got on well from then on, but we made sure the older dogs had the same attention as it had for the 9 years, same with Mindy and Heidi, they both get on well as long both get the same attention at the same time.. Heidi is only fed in the pen and Mindy outside it.
