Hi all , i own a 3 year old entire male gsd and a 10 month old gsd bitch (not spayed). At the weekend we agreed to rehome a 19 mth gsd male (entire) from a family friend as her circumstances had changed and he was being left for very long periods.

Anyway , we allowed the dogs to meet on lead in a neutral place and all went really well , they then all walked together for about an hour with no problems at all, all were happy in each others company. My two were let of lead and i kept the new boy on lead and all was great.

However , when we got home we took them into the garden , still on lead for a while and when we felt comfortable let my 2 off , no probs until we let the new boy off. My male tried to hump him within about 2 mins which he didn't take kindly to and he snapped at my boy and they had a bit of a tussle , no damage but lots of noise. Back on lead they were great again , happy to sniff each other etc. The new boy is crated at the mo until we know him better and my dogs are happy with this, they slept by his cage, lots of kisses through the bars but we haven't been able to progress any further because as soon as we let them all off lead the boys have a go at each other.

Any thoughts as to what to do next as i really don't want to get it wrong and don't want to upset my existing dogs. Not sure if it helps but the new dog was used to living with other dogs and is well socialised as are mine. Look forward to hearing your suggestions.

Em x

Hi Em, it sounds to me that your entire existing male dog is wanting to dominate the new male dog to show him where he stands in the pack, this is normally done with the older male humping the younger male and having a bit of a tossle to show each other who is higher in the pack.
IMO as long as you supervise and of course avoid a proper fall blown fight, I would let them sort their pecking order out with a bit of a tossle.
I have 3 bitches, and when my younger bitch started to mature she had a tossle with my older bitch, up on hind legs, humping, growling, etc, I supervised this and it only lasted a few minutes, but helped them both settle as to who was where in the pecking order.
If what I am reading from your post is correct, I feel this is a pecking order issue, as you say they are fine out for walks, sleeping in the same room etc: and that the new dog has been used to living with other dogs so to me it is a pecking order issue, especially when all are entire and you have a bitch that has not been spayed either.
I am sure others on here will be able to give you more advice and experiences, but I would possible consider having one of the male neutered at some stage, as having a bitch at home too, when she comes into season, you MAY have some problems with both males being entire also.
I have not owned two entire males before, only one entire and one neutered, but have entire bitches here.

your older dog is trying to dominate the younger one and thats normal , the only problem you may have is if the younger one decides he wants to be boss now or as he gets older. for things to work one dog has to be happy backing down.
i agree you need to let them have abit of a scuffle to sort themselves out but under your supervision and i wouldn't leave them alone together until you are completely comfortable that things are fine but i'm sure you know that.
only time will tell whether this will work but seeing as they are ok on the lead and sleeping next o each other  then hopefully this is a good sign. don't get lulled into a false sense of security though as things can chance very quickly over silly little things.
hope  it all works out ok for you.

Thank you all for your replies , so far Bear (younger male) is just backing down and Vadar is strutting about acting all macho. My girl is completely uninterested in either of them . They are still seperated for a fair part of the day and crated at night time but walk together beautifully on lead, bodies touching etc and have short bursts of play in the garden with them both of lead but supervised. Going to take things slowly as he hreally is a lovely boy and i want him to stay x

i think the key is to not force things. we would not allow our newest girl to force herself on the other bitch, so that she learnt the way to behave and not upset my other dog. distraction really was the key and for a while i didn't let them both in the garden at he same time as this was just too much and tipped things over the edge.
it did take a number of weeks for everyone to learn the rules and become more comfortable with each other and a lot of time with me sat in the kitchen with a dog gate so they could see each other but not get silly. it's been worth it though and although i don't think their ever be best friends they play fight now and things don't get over heated but i still calm things down if i think it may go to far.
one thing i did notice was when out walking if i let the youngest off the lead first she would run around and be good but if i let the older bitch off first then the younger one would think it was fare game to run at her and jump and this upset the other dog. i would also call them to me a lot well out and reward them coming back, this would add as a distraction and stop them getting too excited.
lots of walks and training kept them calm round each other and the more energy they burnt off the more they left each other a lone at home, so the more relaxed they became with each other. 

Something else you need to keep in mind, is that when your girl comes into season with two entire males in the house, you may find  any peace that exists between them now, may erupt  into  tension (fights)  .

Not a fan of letting dogs fight it out,  if you have two that wont back down, you may have a disaster  on your hands.

Hopefully , they will sort it out , without going that far,  I think you need to take it slowly and see how it goes, keeping in mind the bitch and her seasons