Random Chicken V2

from visual import *

squareSize = 20
numChickens = 5

fence = box(length = squareSize, height = squareSize)
chickens = [sphere(color = color.yellow) for _ in xrange(numChickens)]
times = []

t = 0

def within_fence(obj):
  return abs(obj.pos.x) < squareSize / 2 and abs(obj.pos.y) < squareSize / 2

while chickens:
  t += 10
  for chicken in chickens:
    v_angle = vector(.15).rotate(random.uniform(0, 2 * math.pi))
    chicken.pos += v_angle
    if not within_fence(chicken):
      chickens.remove(chicken)
      times.append(t)
      print "chicken #%d hit the fence at time %ds" %(numChickens - len(chickens), t)

  rate(1000)

print times