I used Bloodgazer Hatchling (2,1,2); Direbeak Hatchling (1,2,1); Any pet with Flock.
Bloodgazer - Warning Squawk and then Falcosaur Swarm until dies. Bring in Direbeak - Ironskin, Falcosaur Swarm, and Predatory Strike (may need to clean up with another Swarm). If Direbeak dies, bring in 3rd pet and clean up with Flock. I tried it several times, and was able to defeat Foulclaw every time - only variation was whether or not I needed 3rd pet.
Easily done with any fliers with flock. Start with Ikky (1,1,1), Black Claw, Flock. Follow up with Ancona Chicken, (any, any, 2) and flock. As long as debuff from Flock is up you'll still do damage to foulclaw even with crouch up.
I was having a lot of trouble with this fight, because it's tricky due to the 'Boss' buff and Crouch move. Effectively giving Foulclaw 100% damage mitigation for a fair chunk of the fight. I found that Direbeak (1, 2, 1), Sharptalon (1, 2, 1) and Bloodgazer (1, 1, 1) Hachlings worked great, using Falcosaur Swarm and then Predatory Strike. Always keeping the Falcosaur Swarm up when possible because it cannot be applied if Crouch is active and Shattered Defenses is not up. I tried to write a script, I cannot program for the life of me, so forgive me if it is poorly made!
ability(518) [enemy.aura(Shattered Defenses).exists]
if [self(Bloodgazer Hatchling).active]