When is my Border Collie fully grown?
Border Collies are mostly full-grown around the age of 12 months. After this, they might continue to gain a few pounds and build more muscles, but you should not expect your dog’s size to change considerably after his first birthday.
If you own an intact male, your dog’s chest will become broader and deeper as he ages. If he has a rough coat (meaning long fur), this fur will also continue growing.
In neutered males and females, these changes are less apparent.
Some very small Border Collies might already be done growing at 10 months of age. Sometimes, this is due to the fact that they were actually mixed with a smaller breed.
Why is my Border Collie so small?
Some Border Collies stay very small. As described above, this breed was never developed to fit a certain physical breed standard. Border Collies were bred to work hard, make smart decisions, and get the job done! How big exactly they were was secondary to their work ethic and ability.
Some lines produce especially small and light-boned dogs. They have in the last decade also become very popular in certain dog sports, such as flyball, agility and disc dog. Your Border Collie is probably completely healthy and simply a small specimen of the breed.
Of course, you should always check with your veterinarian if your dog’s small size goes along with:
- Vomiting or diarrhea
- Lethargy and none of the typical “bounce off the walls” Border Collie energy
- Changes in coat – such as a lot of hair loss, bald patches or a coat that feels rough
- Changes in eating and drinking habits
If you notice any of the above symptoms, it might be that your dog’s small size is caused by a medical issue – in this case, have him checked out asap!