I bought two bonus lambs that were already started on bottles. I switched them to a nursing pail and they have access to milk all day. All has been going well for almost two weeks. Betsy has decided she likes to chew on the nipples instead of suck and isnt getting milk. Wanda sucks fine. I tried off and on yesterday to get her to suck again and not chew/bite or pull. Nothing worked. So, I put some of the milk in a pail, she drank it all. This morning, I put a pail out for Betsy, she drank her fill and went back to grazing. Wanda still nursed the nipple pail. Ever had this happen? Why?