We have discussed the situation with our vet, and both Louie and Cooper have had recent annual check ups - like within the last few months (March & April). Louie had a full on blood panel & UA as part of a senior check-up, all his levels are good. He did have some urine crystals, but an ultrasound showed no bladder stones. Louie is acting as normal as possible for a 10+ year old dog.
Cooper was recently limping - but after 2 days he stopped, and he is fine now. I believe he probably had a minor sprain in a front leg, as he is running, jumping and playing now.
My gut feeling is that several things have caused some of the problems:
1. I agree with Kelly and others that a big part is Louie is aging and weaker than the others and the other dogs can sense this. Part of this is nature's way of survival of the fittest - altho this is really, really sad to say.
2. The girls recently came out of season, and yes, even tho both boys are neutered - they have not lost the heated desires to breed the girls. And Bridgette is a hussy, and throws herself at the boys, which doesn't help matters at all. We kept the females and males separated as much as possible during the heat period, as we knew that would be a testy time for everyone. I cannot imagine having an intact male around females in heat - it must be a crazy time!
3. Cooper is coming of age at 4 years old. One thing that really stands out for me is he has recently started to 'scratch and kick the dirt or grass' after peeing. Bridgette has always done this scratching for a long time, and she is the alpha bitch here.
I have been told that this scratching is a dominant action.
I don't remember ever seeing Louie or Leila do this scratching.
Any one else observed this 'scratching/kicking' in their more dominant pups?
4. Cooper is a HUGE coward. He is afraid or wary of everything! Noise, strange objects, changes of any kind, you name it and he spooks. Coop has gradually gotten better over the past few years, but still is a fraidy cat with an amazing memory!
For example; he associates using the oven broiler and the smell as it starts to heat up with the smoke alarm, as once I burned the garlic bread and the smoke alarm went off. Since that time, if I turn on the broiler - even before I put anything in to cook - he hides in the laundry room or under the coffee table, and won't come into the kitchen. This was the case last night.
5. Cooper has displayed some bossy tendencies around a few other dogs - namely my sister's dog, Kema, who is extremely timid. Cooper senses that he is braver than Kema, and bossed her from the moment he met Kema, and Kema allows him to do so.
Now that Louie is aging, I believe Cooper senses that Louie is weaker and not so tough, and he acts on that.
We are going to work thru this and will be trying many of the suggestions so many of you have given. Thank you so much for all your help - Louie says thanks as well

!