I am trying use the Fantasy Football Players Collection to get a list of my players stats acrros my leagues for a given season by week using the following API but all the players in the response have value 0 for the stats:

https://fantasysports.yahooapis.com/fantasy/v2/players;player_keys=380.p.29236,380.p.28429,380.p.27619,380.p.31074,380.p.26822,380.p.24045,380.p.29370,380.p.6243,380.p.100003,380.p.8780,380.p.31144,380.p.26650,380.p.29384,380.p.24815,380.p.27789,380.p.8447/stats;type=week;week=1?format=json"

                {
                    "stat": {
                        "stat_id": "3",
                        "value": 0
                    }
                },

Why I am not able to retrieve player stats for a given week??