I have some wonderful stock from Thanksgiving. I wasn't as careful to skim and strain it before freezing. How long is it safe in the freezer? Does the presence of a little fat and a few particles impact its lifespan?

Frozen Stock will keep for months in the freezer. I just used some that I have had in my freezer for 5 months now, and it was perfectly fine!
And don't worry the little bit of fat and particles won't affect the lifespan.

I really like the Rouxbe recipe for rich chicken stock. I like to take it one step further. Instead of simmering on the cooktop for six hours, I put the stockpot into a 250-degree oven, often overnight. It's happy in there, unmolested by direct flame, and all of the goodness of the ingredients is distilled into liquid bliss. Try this with the tomatoes from your garden - use the same technique, but once the tomatoes are boiling on the flame, put the stock pot in the oven and let it barely bubble at 200-250 degrees for several days. Check it after the second day because it can caramelize as it is reduced, and it becomes the perfect flavor base for classic Mexican cuisine! Once your perfect tomato paste is cool, you can line muffin tins with Saran wrap and fill with gems of tomato, freeze, store in freezer bags, and in the middle of next year's worst blizzard you can add the fresh taste of High Summer to any dish.

I noticed the bottoms of the garlic heads were already either trimmed or cleaned of dirt and roots, and the leeks were not cleaned at all. Given that other recipe(s) on Rouxbe highlight the importance of cleaning leeks, I'm curious why the cleaning was omitted.

Secondly, I was talking with a chef the other day and he said he never uses celery leaves in his soups or stocks because they impart bitterness. (This is based on a test stock he made from celery leaves.) Is this your experience also?

I made this will I cleaned the house. What a great smell, certainly better than any cleaner.
I was so happy with the end result, really nice color with the tomatoes.

In the recipe you state that chicken bones are used however in the video you can see chicken on the bone. Please can you let me know what I should do.

Chicken bones, backs and necks is what we used in the video. Perhaps it looks like meat on the bone, but I assure you they were just bones. Bones will still have some meat attached to them, which will add lots of flavor to the stock.

If you had meat on the bones though you could also use that to make a broth rather than a stock, see our Broth Lesson in the Rouxbe Cooking School - http://cheetah.rouxbe.com/school/sections/20/objectives

Hope this helps!

dont worry about the meat on the bones.
next time you do this, try not to be cheap and put the whole bird in, wings thighs and breast still intact.
u might want to ask your butcher to remove the skin though...
there is nothing in the world that is better than a chicken stock made with a whole chicken or two

Indeed you can add meat to the stock, essentially you would then be making a broth. We go into in more detail in the cooking school lesson on How to Make Broth. We also talk about it in How to Make Broth Soups. Cheers!

Just got my first attempt at stock making on the stove! Waiting for it to get to simmer point. Very pleased with myself! Thanks Rouxbe for your great recipes, videos and advice!

The chicken bones were free from the butcher - how marvelous! FREE - you never get anything for free these days!

Cooked for 6 hours, strained and chilled in fridge and have removed the fat from the top. My stock is not very clear, its rather murky. Do I need to strain it with cloth to get rid of ALL the bits?

Depends on what you are using it for really. If you desire a nice clear stock then you can go ahead and strain it again. If using it for things that don't require a clear stock, such as stews etc. then dont' worry too much about it. Taste it what matters most. If it taste good then you are good to go. Cheers!

Just put this on the stove now. I could only get 4.5 quarts of water in there. So..... just go with that and have a richer stock? Or.... add water at some later point in the simmering as room becomes available? If I add water later, should it be cold water or hot (to match the stock temp)?

As long as the bones and other ingredients are covered then you should be okay. As you thought, you will just have a more intensely flavored stock, which is not a bad thing. If you do need to add more water to ensure things are covered then you should use cold water (as mentioned in the lesson on Stock Making Fundamentals). Cheers!

I had some left over bones and threw them in a pot and then came to find this recipe. I haven't used the stock yet but the smell was delightful. I put it in two bags and froze this morning. I'm really looking forward to using it.

The only thing I regretted was not having a use for the vegetables. I would have pureed and given to the dogs if not for the onions. I'll figure out something.