my 8mth old male becoming aggressive to my 13yr old male

Please can some one help, my 8mth old male puppy who is usually very loving and lives with his 8mth old litter mate, who is a girl and our 13yr old male. The puppies have been with us since they were 2mths old. Our 13yr old was very wary of the puppies at first, seemed they were too small for him. As they grew our 13yr old became more confident with them starting to play with them, when he had he energy! Now in the past few days our 8mth old male has started lashing out at the 13yr old. We think it may be a food sharing issue, bones was a big no no both times we tried to introduce the treats the 8mth old attacked our 13yr old. We are now having to supervise meal times. The 8mth old seems to be jealous but he gets a lot of love and it is shared equally between all three dogs. He will wait when commanded, stay until called really coming along well. This issue is very unsetting for us and is obviously putting our 13yr old on edge and seems to be confusing our 8mth old girl, there seems to be tension in the room after an incident, maybe thats what we think and not the case but it certainly seems to be the case. Also the 8mth old male will urinate over both the 8mth old girl and 13yr olds urine after they both go to the toilet.

how many time do you walk them and how long for per day?

I've moved your post to SBT chat it'll gets more views here, could it be a dominance thing?

Perhaps you could come say hi :- https://staffy-bull-terrier.niceboard.com/f7-new-member-introductions

Maybe a dominance thing as Hayley says, and exercise is very important indeed as Steve has asked.  

I'd hazard a guess at a dominance issue too. 8 month boy beginning to find his feet.

I'm afraid I can't help on this one as I have never had more than one dog at a time, but I'm sure you'll get some good advice shortly.

the puppies are walked in the morning for 30mins. They have a very large garden which they spend alot of time in playing and chasing each other. 13yr old does not walk with puppies but spends time in the garden with them

You are going to have to make sure they all get enough exercise and be very watchful. The young buck might be feeling his oats and wanting to rise in the hierarchy. This can happen. You have to be careful not to let them get into it.

Thanks everyone for your imput puppies are going to get more exercise it seems to be whats lacking, hi viz jackets on the way for the dark mornings!  

2 males + 1 bitch = fights.

First off let me start by saying ... When I was reading this for some reason I was under the impression that it was your 13 year old son and not a 13 year old dog.. Weird at first but I kept on.. Got to the end with the pee and I was like wait a second ! lol sorry thought I would share and maybe give you a laugh!

Moving on, all I can say is even though they have been together since they were little pups, I think something like this was bound to happen. It is normal for younger " up and coming " animals to want to "push the elders around, and assert his dominance as the "Alpha" male. Just the fact that the young male is covering up both pee spots shows that he is determined to "run" the pack. Having 1 bitch and 2 males is proly the worst scenario you could have. As long as the 13 year old becomes very submissive this should blow over after some time. If not you may have to keep supervised meal/play times and maybe even seperate them. Good Luck! Keep us posted