You probably had only 2.5 pounds. The current UI (to be changed in the next version, I think) only shows a rounded up amount, so two "2 pound" pieces of fur may actually weigh e.g. 1.4 and 1.1 pound respectively. There ARE losses if the extra bit is very small, possibly compared to the total, but you ought to get anything more than 0.1 pound as a remainder, so you shouldn't actually have had more than at most 2.6 pounds.