Simplify the following text for a Grade 7 native English-speaking person.
Original: Hip dysplasia is a major problem for the breed , with 63.8 % of pugs being affected according to a survey performed by the Orthopedic Foundation for Animals , and they were ranked second worst affected by the condition out of 157 breeds tested .
Simplified: Hip dysplasia is another major problem for pugs . About 63.8 % of pugs were caught with hip dysplasia .