Three weeks into the season, half of the Big Ten’s dozen defenses are under aerial attack.

Six of the conference’s teams are allowing 250 or more yards passing a game, and, if you count Nebraska’s 299.7 yards-against average, three are giving up 300 or more.

Big holes in pass defenses played were a big reason why the Big Ten went 7-5 last weekend, including 1-3 against Pac-12 schools.

Iowa coach Kirk Ferentz says he doesn’t usually pay much attention to stats this early in the season, but he took a painful look at the end of last weekend at the conference numbers.

“Gosh, it’s amazing how many yards — I’m just looking at the Big Ten stats — how many yards and points are being scored,” he said. “It really makes you wonder if anybody’s playing defense anymore.”

Iowa (2-1) is sixth in the Big Ten in pass defense, giving up 220 yards a game. Of the teams giving up passing yards in the biggest chunks, Illinois is the worst at 330.3 yards a game. They’re followed by Northwestern at 319, Nebraska’s 299.7, 257.3 for Ohio State, and Purdue and Michigan both at 256.3.

Not surprisingly, five of those teams — all but Ohio State — are also in the bottom half of the conference for scoring defense. Nebraska (2-1) brings up the rear, giving up 29.3 points a game.

UCLA threw the ball for 294 yards Saturday in its 41-21 win over the Cornhuskers Almost half of those yards were in the third quarter, when the Bruins scored four touchdowns and took over the game. Nebraska coach Bo Pelini said his defense played a good game, or at least part of one.

“We let things snowball and it got us out of our technique, it got us out of our execution,” he said. “In this day and age, especially when you’re playing spread teams — I told the team we’re going to give up some yards every now and then.”

That echoes many coaches, who say it’s hard to keep offensive numbers down with the proliferation of spread offenses and teams that play hurry-up for most or all of a game.

Illinois (2-1) watched Washington run 85 plays last Saturday in its 34-24 loss to the Huskies. Perhaps the biggest surprise is that Washington didn’t score more points. The Huskies passed for 342 yards and ran for 273 more — a stunning 615 total yards.

Illini coach Tim Beckman has pointed out since the preseason that his secondary is very young. Only one starter, junior safety Earnest Thomas, came into the season with any serious experience. But against Washington, coverage wasn’t the primary problem. Tackling and a lack of pressure on Huskies quarterback Keith Price were, Beckman said. Illinois sacked Price twice, but otherwise only got near him three times on pass plays.

Washington made Illinois pay with big plays as six Huskies caught passes of 15 yards or more.

Price, Beckman said, is probably in the “top couple” of quarterbacks the Illini will face all year.

“We know we’ll be tested again,” Beckman said, “but he did an outstanding job of eluding our pressures and making plays on the run.”

Urban Meyer isn’t ready to concede that giving big plays is a given when his Ohio State team (3-0) plays a team like Cal. The Buckeyes beat Cal 52-34, but Golden Bears quarterback Jared Goff threw for 371 yards and three touchdowns. Three of those passes went for 61, 42 and 26 yards.

“I hate to accept it,” Meyer said. “I think we’re more prepared to give up (shorter passes) because they’re so quick getting the ball out and the quarterback’s really an accurate passer. The big plays, there’s really no excuse for that.”

Conference play starts over the next two weekends and the defenses will be matched up against a group of offenses rolling up big yards. All but three Big Ten teams are averaging at least 437 yards a game, and five of them are passing for at least 250 yards a game.

Northwestern coach Pat Fitzgerald, a linebacker for the Wildcats (3-0) in his playing days, is another coach who chalks part of his defensive problems up to a young secondary. The thought of a potential offensive explosion when Big Ten offenses face those defenses makes him cringe.

“I hope not,” he said. “As a defensive minded guy, I hope not.”