Found lots of cockatiel feathers this morning. Any help!?

I came down this morning and found 35 feathers on the floor. not the little fluffy one but big flight feathers. We have 2 cockatiels and we see them have little spats with each other, but nothing serious. Their wings and tails look really short,and on the feathers that fell out there is blood on the end, and some have been ripped. They are both fine now, preening each other in fact, but not 'pulling out feather' drastic. Any help?