does Lay on hands mastery work with passive skills? 

Yes.

for example I have klodd beastfeeder who has passive that heals an ally by 10% of their max hp but does this skill increase it to 15%? 

No. Healing skills, unlike debuff chances, get increased multiplicative, not additive. You don't get 10% + 5%, you get another 5% of 10% (10 x 0.05). The passive will heal for 10.5% with lay on hands.

okay I found it out myself it is 5% of the 10% so i don't think it's worth it but if you use it on champion like mother superior who has 60% heal it would be more useful