My puppy is six months old now, and she's huge. She's a little over sixty pounds. She isn't overweight. There's not a bit of fat on her. In fact, for a while I was afraid she wasn't eating enough, but her ribs are just perfect. I free feed her through the day up to the maximum suggested amount on the bag, but she's rarely eaten all of it. There's always at least a cup left in her bowl when we go to bed at night. I was feeding her Nutro Large Breed Puppy, but on the advice of my vet I've switched to Pro Plan large breed puppy. She's always been pretty big. At 10 weeks, she was 30 lbs. Her sire is a very large lab. Do you think she might be too big for her age? Should my next bag of food be adult food? Also, how old should she be before I can give her glucosamine supplements, and should I give it to her?
Also, I have a question about her first heat. She hasn't had it yet, and I was wondering if there will be any signs before she starts. We're considering breeding her eventually if she passes all her hip and eye exams when she's two. She's a beautiful dog with excellent championship lines, but if we don't feel that it's the best thing for her when we get to that age, then we'll get her spayed. Until then, I'm willing to help her deal with her seasons. I know a lot of people will probably tell me not to breed her because there are enough unwanted dogs out there, but I plan on finding homes for her puppies before I breed her, IF we do decide to breed her.
To summarize (my, this became a long post) is my dog too big for her age and what signs will she exhibit, if any, before her first heat? Also, how old should she be before I can give her glucosamine supplements, and should I give it to her?
Thanks, I really appreciate any input you can give me.

Sounds like you are doing well. My background is with guide dogs, and nobody know more about long active lives for Labs than the dog guide schools. The school I raise puppies for switches their Labs to adult Pro Plan at 4 months. They never give glucoseamine. Other schools use a slightly different plan.

I do all I can to discourage irresponsible breeding. You sound like you have read the guidelines at www.akc.org and more. As she starts producing hormones, the first sign may be flaky behavior, often clingy. The vulva usually swells a week or 2 before the discharge. As she progresses, you may be amazed at her strenuous, creative efforts to get loose and go find a male. Be extremely careful with her. Once loose, much worse can happen than an unplanned breeding.

There are Seasonals and other brands of garments that Velcro to her and hold a sanitary napkin. Makes keeping her in the house and even taking her out much easier. She may smell terrible. Put up with it, not bathing her until she is all done and the swelling goes down. If you watched her carefully, don't panic if she starts to look pregnant. Many Labs do very convincing false pregnancies after their first season. I have been through this with Taffy, Aster, Daisy, Peggy, Lola, Tulip, Kate, and Gretchen who was a Shepherd rather than a Lab. The dog guide school wants the option of selecting any of their puppies as breeding stock. My Gretchen was.

http://www.photolocker.net/images/Labman/proplanc.jpg

It is unusual for a Lab not to snarf up anything it can get leading to life shortening obesity. It sounds like you have a big girl that is an exception. When she is in for shots, have your vet confirm your judgment of where she fits in the above chart.

Oh, I want to add, they have most of their size by 6 months.

Also, I forgot to ask, but is there anything I can do about her passing gas? She has the *worst* smells coming from her. It doesn't seem to cause her any discomfort, but it makes my eyes water, it gets so bad.

They sell pills that are supposed to help, check better pet supplies. Many years ago, I reduced the problem by changing feeding time to bed time. The dog was in the house much of the time, but slept outside. That was before I discovered crates. Middle of the night bowel movements weren't a problem.