Considering this study will look at behavior tendencies in connection with genetics, I have to mention that the she-dogs also have to fluctuating hormones. My females is 13 1/2 months old and going through her 2nd heat. A couple of weeks prior she started acting differently. Instead of my brave pup I had a shy gal (unless she was playing her favorite game). If she had been a human I would have said she was an angsty teenager.
There are some reported health benefits with leaving dogs intact, especially while they are actively growing. I don't intend to breed my gal so she will be altered, most likely after her third heat. I had considered having an Ovary Sparing Spay but with these mood swings, I think a full spay just may help her be a confident gal year 'round. Has anyone noticed this in their females, in particular the mood swings? All my previous females were spayed young or before I adopted them.