Why are you getting eggs every 14 days.?? Are you not letting the hen sit on any eggs/dummy eggs for any period of time. The normal cycle would be that a bird would be sitting for between 18/23 days to hatching and then feeding the babies for a period of time giving her body time to replenish it's own resources. If you have been just taking eggs she will continue to lay more every 10/14 days. If this is what is happening and you have been doing this for any length of time it is no wonder that the bird can't walk.