Hello, I have a 7 month old male English Mastiff puppy who goes to sleep and wakes up bigger. LOL His weight is currently 105 lbs and his height is about 26.5" to shoulders. His neck is 20". I wonder how big his neck will be when he's fully grown. I have a 2 year old female English Mastiff who is only 125 lbs 27" tall to shoulders, and her neck is 23.5". I'm pretty sure my male puppy will have a bigger neck than my female. Could other English Mastiff owners share how big your English Mastiff necks are. If you can also include their weight and age, it'd be really awesome and most appreciated. Thanks in advance everyone.