Other mistake: After Nick and Fetcher arrive at Tweedy's Farm for the first time and introduced themselves to Ginger, she hands them a bag of seed, but where did the bag come from? It definitely was not there when Nick and Fetcher are showing Ginger their stuff for sale. (00:11:00)
Other mistake: Ginger is adamant that she will not approve any plan of escape that does not get all the chickens on the farm out and to freedom. The problem is, not one of her plans gets anywhere close, and it is not that they fail to liberate the whole farm - they are never planned that way. We see her trying to escape by herself three times. The mannequin of Mrs Tweedy would (had it worked) have allowed nine chickens to escape, the upturned feed tray just seven. Even the 'crate' appears to hold not more than thirty chickens - and there must be several hundred on the farm, at least.
Other mistake: In one or two long shots for the head counts you can see all the chickens in the entire farm lined up outside. There are at least two hundred of them. In all other scenes and on the escape vehicle, you never see more than 20 chickens or so. Where did all the others go?
Other mistake: When Ginger finds the bottom of Rocky's poster she takes it out and lines it up with the top half ...and it stays there without any sort of support (we see the back of it as she approaches the poster, and there's nothing there which will stick it).
Other mistake: Mr. Tweedy was kicked up the bum, and later he is shown rubbing Mrs. Tweedy's bootprint. He should have a different mark, because he was kicked, not pushed. In the next scene, the mark has disappeared.