Well first off they need to be introduced slowly not just put together and asked to play nice. place them into separate pens where they can see each other but can't touch do you have them outside? let them get to know each other daily by living side by side. Then after a few days while your there give them time together.but still keep them separate when you can't be with them. hopefully by weeks end they will be best friends.
x2.
Dogs are big enemies of geese naturally so this will take alot of time to work out, patience and keeping them apart but where they can see each other and hopefully the new goose will get us to your dog. All of it is going to take time but if you go about it in the right way it will work out.
Hard to say waterfowl have a way of splashing most of their water out all over so do a trial run today. So she spent alot of time stressed. Not good for a young gosling or goose. Well just means it's going to take time for her to feel at home around yor dog and just being in a new place is stressful so Try to be patient and give them as much outside time as you can ,being in a large area may relieve some of the tension between the 2 goslings. [without the dog]
