How many mice are required to find the poisoned can?

The number of mice is not related with the time and with any thing...
I think only ONE mice is required because if we take one mice and if the first can is poisoned then it will die or else we will test for 2 can and so on...and the death time of the mice is not mentioned..who knows it may die after taking poison.

5

7 mice

5

Pick 5 mice
Assign binary codes to 30 cans. you need 5 bits to represent all 30. Pick 5 mice to represent each bit. Have a mice taste all the cans for which the corresponding bit is one. After 14 hours, some will die and some wont. Set 1 for the former and 0 for the latter. The corresponding bit representation is the poisoned can.

2

3 mice. Divide the cans in three groups with 10 cans each. Feed each mice from one can from the three groups. Wait one hour then feed them with the second can from each group. Continue 10 hours until all the three mice ate from each of the 10 cans in their group. Then wait and see which mice dies and when.