After the chicks were born, the hen jill started fighting with jack when he tried to feed the chicks. She would chase him away and knocked him against a wall. she is still doing it. Is this normal?

I wouldn’t say it’s normal, but it happens sometimes, it might be best to remove the cock as often once this happens they can badly injure the cock or even kill him. How many chicks do they have, she probably could feed 3 or 4 by herself. If they have more it would be better if you could foster them to other pairs if you have some. I just looked at you details it doesn’t look like you have any more pairs. If you have more than this number of chicks & some are well feathered & you have another cage you can try some of the older ones with the cock bird.

I agree with Norm. The hen and the male need to be separated. I hope your friend has another cage. I like Norm's idea of putting some babies with each parent. It will reduce the stress on all her birds.

Also, time to remove that terrible excuse for a nesting box. The hormonal attacks may be due to it. Chicks are old enough now not to have the nesting box / plastic container thing they are in.......and from what I can see, your friend has chosen to breed in far too small a cage with not the right kind of setup. ....so the hen will be anxious with all those babies in too small a space.