Boosts aren't nothing, they increase a Wolf's ability of the boosted cp attribute it's in. Defects aren't nothing either. Depending on the defect it will affect the coat of a wolf, have negative affects to specific cp attributes depending on the defect, and a few defects don't affect anything at this time
Nimble foot gives a boost to agility, instead of the usual limit of 200 CP that can be given to agility, the wolf can receive 250 total cp in agility. It will have better agility than wolves without the boost
Dwarfism has a 50 CP penalty in both agility and battle.
As your wolf has both a 50 CP boost in agility as well as a 50 CP penalty in agility, it basically doesn't affect agility either way. However the wolf will still have the 50 CP penalty in battle from the dwarfism.
For more information on boosts and defects you can check these threads out
Boosts: https://wolfplaygame.com/forums.php?f=29&t=102
Birth defects: https://wolfplaygame.com/forums.php?f=29&t=101
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