I have an 18 month male and an 8 month female. I don't want to breed them. I don't want to spay or Neuter until they get to full size. I have a fairly small house and yard. What are recommendations for when she goes into heat and how obvious will it be based on behavior of both dogs?

I am looking for specific ideas on what to do with the dogs during heat cycle. Board one or the other? Keep them in the house in crates and separate rooms?

Thanks!

Both are adult enough to be spayed and neutered NOW. Why would you allow her to go into heat? You are setting yourself up for big problems.

It will not stunt their growth to spay and neuter now. It's actually the safest, and most sure fire way to prevent un wanted pregnancies. There is no health risk to getting them altered now. There are injections that you can get for your male which will temporarily stop the production of testosterone and he can not impregnate the female.

The thing with waiting is, you may not even notice your b!tch going into heat, and it only takes once for them to mate and you could have a litter of puppies on the way.

Some people recommend Danes be spayed later, I see no problem with waiting if you are prepared to be VERY diligent in keeping them apart. Of course, an early spay is the safest option to avoid a litter plus larger breeds tend to come into season later than smaller breeds, usually closer to the 11-12 month mark. By then her height will be finished then anyway.

My mother had a b*tch in full season jump through a glass window to get to a male (yes, it's not just the males who try to get out!) So you will need to be very careful if you decide to wait.

Boarding the male is a good idea, I would never board a female in season though, it is not fair on the other dogs at the kennel plus some refuse to take them anyway.

It will cost a bit as he will need to be boarded for 3 whole weeks.

Seasons are messy with any breed, but with Danes, due their size it is a lot worse.
Cover all couches, chairs and beds with old sheets, if you have carpet it might pay to lay some sheets down in high traffic areas as well to get the drips.
They do make doggy diapers or b*tches britches but that is something you would have to buy when she comes in to get the right size.

Crate and rotate would be a way to keep them both in your house. Keep one crated in a large crate or room while the other one has free roam, then switch it up.