Hello
I would be ever so greatful for some suggestions to helping my dogs.
I have 4 dogs
Milo (7 yrs, neutered, very small jack russell terrier)
Basil ( 14 month old large jack russell / neutered 3 weeks ago)
Tweak (5yrs old spayed ***** jack russell)
Edy (6 yr old neutered large jack russell)
About 9-10 weeks ago basil and milo started fighting, over seemingly nothing. Then after broken up they would go back to living together. Sleeping together. Exercising together. .. this continued and escalated to about twice a day.
We consulted with a behaviourist and started muzzle training basil (he was the one causing damage when fightinh) we put baby gates through out to separate the 2 and things calmed down for about a week-2 ..... they had exercise and mental stimulation increased. Dap diffuser. Basil was taken in to be neutered then I had the flu and was unable to do anything for 2-3 weeks inc take dogs out.
2 weeks ago they had a massive fight (the kids had left the gates open and basil wasn't muzzled) and since then they need to be 2 gates apart or fight as soon as they see each other...... I have re increased exercise. I have been working on obedience to build a strong bond with them both.
I had started counter conditioning but I'm not sure if I'm making things worse as they either want to kill each other in the same room or get away and out of the room so by forcing them to be in the same room to treat them is a stressful situation for them both.
Milo seems to be the one initiating the fights and although basil is the one who causes the bites / puncture wounds he seems to be the "nervous" one of the 2.
Edy and tweak don't get involved in the fights and basil and milo both know that edy and tweak are the biggest grumpiness out of the 4.
I know I have written this quick so if any more info needed let me know
Help please.

Thanks in advance