Six months to Adulthood Bulldogs are considered puppies until they are about 18 months old. So your puppy should continue on a puppy food until that age. As your puppy grows into adulthood, he will put on an average of 6 pounds over the next six months, or about a pound a month if being fed a nutritious, growth-supporting diet. An adult female will ultimately weigh about 40 pounds, her male counterpart about 10 pounds more as they continue to put on muscle and "fill out" over the next two years.